Harry Potter), movies , video games , graphic novels  and TV series . We propose that imaginary worlds are popular because they activate exploratory preferences that evolved to help us navigate the real world and find new fitness-relevant information. Therefore, we hypothesize that the attraction to imaginary worlds is intrinsically linked to the desire to explore novel environments and that both are influenced by the same underlying factors. Notably, the inter-individual and cross-cultural variability of the preference for imaginary worlds should follow the inter-individual and cross-cultural variability of exploratory preferences . We test these predictions with both experimental and computational methods. For experimental tests, we run a pre-registered online experiment about movie preferences (N = 230). For computational tests, we leverage two large cultural datasets, namely the Internet Movie Database (N = 9424 movies) and the Movie Personality Dataset (N = 3.5 million participants), and use machine-learning algorithms . In all, consistent with how the human preference for spatial exploration adaptively varies, we provide empirical evidence that imaginary worlds appeal more to more explorative people, people higher in Openness-to-experience, younger individuals, males, and individuals living in more affluent environments. We discuss the implications of these findings for our understanding of the cultural evolution of narrative fiction and, more broadly, the evolution of human exploratory preferences.Imaginary worlds are present and often central in many of the most culturally successful modern narrative fictions, be it in novels (e.g.,  Star Wars is the most lucrative media franchise in history. Harry Potter is the best-selling book series of all time. Game of Thrones holds the all-time audience record for a TV series. One Piece is the best-selling manga series in manga history. The Avengers: Endgame is the highest-grossing movie of all time. And Zelda is the best-selling video game series in the history of video games. They all have something in common: their creators developed an imaginary environment, that is, a fictional environment that does not actually exist, which is different from the real world, and that the consumers know to be partly or fully invented4. Moreover, such fictional stories with imaginary worlds appear better at building huge fan communities, as exemplified by the fact that lots of them turn into highly profitable multimedia franchises . In other words, modern culture, from movies to clothing to theme parks to educational tools, increasingly revolves around imaginary worlds. Why is there such a massive interest in fantasy worlds? What lies behind this anthropological phenomenon?The cultural importance of imaginary worlds in contemporary societies cannot be overstated. 5. This preference is best described as an evolved cognitive mechanism that processes cues of new or information-rich environments as inputs and delivers an adaptive approach behavior as the output: it makes people environmentally curious and prompts directed exploration . This mechanism of environmental curiosity was selected because it enhanced fitness in ancestral environments, motivating humans to discover new habitats, new cooperative or sexual partners, resources such as food or water, and new fitness-relevant information17. It explains, for instance, universal walking patterns integrating multiple changes of directions .In a theoretical paper, we proposed that imaginary worlds in fictional stories artificially trigger the human preference for explorationThe Lord of the Rings”, and other fictions with imaginary worlds, relies on the “intrinsic feeling of reward” we experience when “viewing far off an unvisited island or the towers of a distant city” . This statement is very close to the one of Shigeru Miyamoto, the creator of Zelda, who reported that he “wanted to create a game world that conveyed the same feeling you get when you are exploring a new city for the first time” (1989). Following the same intuition, we hypothesized that humans are fascinated by imaginary worlds for the same reasons, and under the same circumstances, as they are motivated to explore new and unfamiliar environments5. It is equivalent to saying that imaginary worlds constitute a superstimulus of explorable environments20, or that imaginary worlds are part of the actual domain of the cognitive mechanism that evaluates landscapes , just like masks are part of the actual domain of the cognitive mechanism of human face recognition21.Because imaginary worlds are unknown fictional settings, they can be seen as new environments that consumers discover. As Tolkien put it himself, “part of the attraction of 22; see also23) because we reason that different forms of curiosity should not be sensitive to the same cues to orient attention and behavior. Relying on some recent molecular evidence, Hills24 has argued that spatial exploration and cognitive exploration are linked at the phylogenetic level: “What was once foraging in a physical space for tangible resources became, over evolutionary time, foraging in cognitive space for information related to those resources” . Here, we focus on environmental curiosity, that is, on the specific curiosity for environments that prompt spatial exploration while recognizing that exploratory preferences may exist as a more general cluster26. For instance, there is experimental evidence that a preference for spatial exploration in a foraging task is associated with a preference for cognitive exploration in a problem-solving task27. In any circumstance, there seems to be a cognitive mechanism that specifically processes landscapes29.Let us note that we differentiate between spatial exploration and cognitive exploration, and symmetrically between environmental curiosity and other domain-specific forms of curiosity . For instance, participants in unfamiliar lab settings choose more exploratory optionsthem to explore more.In this paper, we further test the exploration hypothesis. In Study 1, we first explore the importance of environmental curiosity in structuring the landscape of contemporary fiction. Fictional stories can trigger a range of human motivations, from romantic love  to threat detection  to causal reasoning . However, not all motivations are equally important to fiction: typically, eating food or discovering new smells are important to humans, but marginal in fiction, for reasons beyond the scope of this paper. Consequently, while fictional stories about food or perfumes do exist, they are relatively uncommon and not generally considered as belonging to a distinct genre. On the contrary, if exploration is one of the most important psychological factors in contemporary fiction, it should structure the landscape of contemporary fiction. We should observe that, when organized by semantic proximity, fictional stories with a strong emphasis on environmental curiosity, particularly those featuring imaginary worlds, should cluster together, and should cluster apart from other large, well-identified genres, such as romance or horror fiction. In Study 1, we also test that fictional characters in stories with imaginary worlds navigate their environments more than in other stories. This prediction relies on the idea that the psychology of fictional characters should be crafted to be consistent with their fictional environments: their evaluation of resourceful or informative landscapes should motivate 5, we predicted that if the exploration theory is valid, then the attraction to imaginary worlds would be intrinsically linked to the desire to explore novel environments and that both would be influenced by the same underlying factors. In other words, we predict that each source of variability that explains inter-individual differences in the sensitivity of environmental curiosity should also explain inter-individual differences in the consumption of fictional stories with imaginary worlds. Before testing this mapping between cognitive variability and cultural variability, we further explain the origins and the mechanisms underlying inter-individual variability in environmental curiosity.In studies 2 and 3, we develop a set of empirical predictions derived from our theory. In our theoretical paperexploration–exploitation trade-off , which is dealt with differently in different species according to their life history strategies . Crucially, this trade-off is also dealt with differently between individuals from the same species, including Homo sapiens. This is best seen in the inter-individual differences in spatial abilities52. We contend that sources of adaptive variability explain the inter-individual differences in people’s motivation to explore. First, we review the literature in evolutionary psychology and associated empirical evidence showing that the sensitivity of human environmental curiosity varies according to adaptive sources of variability. We select four of them that seem to explain a significant part of the variance while acknowledging that other factors could be added to increase the explained variance.When and why should organisms decide to explore or not to explore? This question is best known as the evolutionary 55: people are genetically hardwired to be more or less curious. This is captured by the existence of a genetically inherited personality trait often called Openness-to-experience58. It constitutes one of the five dimensions within the Big Five, the model of human personality59. The five dimensions that compose it  have been designed to capture the universal variability of human personalities and behaviors: humans differ in the personality “scores” associated with each of these dimensions. The Big Five is considered the most widely accepted model of human personality today64.The importance of exploratory preferences varies at the inter-individual level according to some fixed personality traits, which are thought of as evolutionary strategies of specialization to some ecological or social niches65, a preference for creativity71, spatial cognitive capacities75, a preference for using maps76, a preference to explore a system78, and innovative deviations from observed demonstrations in learning tasks79. In other words, people higher in Openness-to-experience are overall more curious and explorative80. In the cultural domain, the Openness trait is correlated with the liking of adventure movies, fantasy movies, and science fiction movies81, the enjoyment of abstract art82, the preference for jazz, blues, classical, rock, alternative, and folk music85. It also correlates with some cultural practices reported by people, such as going to the theatre, art galleries, or museums86, or seeking novel food87. We, therefore, predict that people higher in Openness should be, on average, fonder of fictional stories set in imaginary worlds.The Openness trait is correlated with novelty-seeking behavior90. A complementary explanation posits that the evolutionary costs associated with exploration  are outweighed by parental caregiving investments92. This can be seen as an adaptive feedback loop or as an adaptive developmental division of labor95.The sensitivity of exploratory preferences varies according to the developmental stage of the individual. Evolutionary developmental psychology explains why: younger individuals have more to learn from the world, so it is more adaptive for them to explore their environments and try to reduce knowledge gaps96, for a review). Children are more explorative than adults in foraging tasks99, in bandit tasks100, in explanation-seeking tasks102, in search tasks103, in decision-making tasks105, in problem-solving tasks106, in causal-learning tasks108, and in change-detection and visual search tasks109. Importantly, such behavioral data from experimental research and computational modeling show that children are not merely prone to random sampling behavior: they show clear patterns of directed exploration110. Another study found that intellectual curiosity is negatively correlated with age, after controlling for education level, sex, and culture111. In a foraging task, adolescents explored more and more optimally than adults did112, consistent with other findings suggesting that adolescents too are more motivated to explore novel, although risky, scenarios than adults117. In accordance with such findings, Openness has been shown to decline with age across countries122. We, therefore, predict that younger people should be, on average, fonder of fictional stories set in imaginary worlds.There is already much experimental evidence that children are indeed more curious and eager to explore than adults : in this view, spatial exploration is thought of as a male reproductive strategy126. For instance, in humans, there is evidence that, in the Tsimane , males travel more than females, and even more so during periods of intensive mate search127, but not earlier in ontogeny75.The sensitivity of exploratory preferences varies according to an individual’s biological sex129). Both rationales can explain why, in humans, males develop higher spatial abilities specifically related to exploration than females  and navigate in wider ranges than females .Another evolutionary rationale posits that, in humans specifically, exploratory preferences and abilities contributed differentially to the reproductive success of males and females because of the sexual division in foraging activities: males would have specialized in solving spatial problems associated with hunting (which requires a propensity to explore unfamiliar environments) while females would have specialized in solving spatial problems associated with plant gathering  in hunter-gatherer societies , males explore more land, follow more sinuous paths, walk further per day144, and also perform better in three tests of spatial ability145. We, therefore, predict that males should be, on average, fonder of fictional stories set in imaginary worlds.Overall, three different  evolutionary hypotheses propose that some adaptive challenges human males specifically faced during their evolution  led males to be more systematically curious about their spatial  environments while leading females to be more systematically curious about their social environments. This is consistent with the findings that (1) in modern societies  males score higher in the personality trait Openness-to-experience148. Why? In unsafe and poor ecologies, exploration is very risky, notably because if exploration does not pay off, one is left with nothing. Relatedly, the opportunity costs of exploration are higher in scarcity because one is better off exploiting one’s environment to provide for more pressing needs. Conversely, in more affluent, safer, and predictable ecologies, such risks are lower: notably, when surrounded by more resources, individuals can afford to lose some of them in the short term149. Therefore, exploration is best defined as a ‘venture behavior’, that is, a preference for a high variance of rewards over short-term gains (as opposed to ‘hazardous behavior’150). Since organisms evolved in changing environments151, selection pressure would have favored exploratory preferences that are highly flexible to the local ecology, with time horizon as the crucial mediator152.Finally, exploratory preferences are hypothesized to vary according to the local ecology of an individual. Exploration is most valuable and adaptive in more affluent, safer, and therefore more predictable environments153 is observed in a wide range of species, such as in orangutan156, honeybees157, parrots158, and chickadees159. It is parsimoniously hypothesized that it applies to humans160.More generally, phenotypic plasticity enables an organism to adapt to new situations and environments by changing its behavior, rather than having to wait for genetic adaptations to occur. This flexibility in behavior can be an advantage in unpredictable or changing environments, allowing organisms to survive and reproduce more effectively. The behavioral effect of the local ecological cues on exploratory preferences, curiosity, and spatial search strategies162 and that people with higher income at one stage of their life are less likely to decrease in Openness-to-experience later on163. In a foraging task, people with more adverse childhood experiences remain in patches longer and, thus, explore less164. At the level of societies, recent empirical studies show that, across the world, people living in more affluent countries exhibit higher levels of openness to change and new experiences167. Finally, a recent study shows that between-countries differences in levels of causal learning and pretend play in children  are similar to those within-countries due to different socio-economic statuses . We, therefore, predict that people living in more affluent local ecologies should, on average, be fonder of fictional stories set in imaginary worlds.At the individual level, there is empirical evidence that people living in richer families score higher in Openness-to-experienceWe reviewed evolutionary rationales and empirical evidence showing how the human motivation to explore  adaptively varies according to people’s personality traits, age, sex, and ecological conditions Fig. .Figure 120. If imaginary worlds do exploit this cognitive mechanism, the sources of its adaptive flexibility that we reviewed should account for the variability in the human fascination for imaginary worlds, across time and populations.Our hypothesis, therefore, leads to fine-grained predictions based on the adaptive variability of environmental curiosityBefore testing predictions about the sources of variability of the preference for imaginary worlds, we straightforwardly investigate whether fictional stories with imaginary worlds are related to exploration. We test that (1) stories with imaginary worlds constitute a well-identified cluster in the global set of movies produced and that 2) this emerging cluster is related to environmental curiosity through exploration-related content. We use independently two machine-learning algorithms. The random-forest algorithm, based on manually annotated movies, and trained on plot keywords, is designed to detect imaginary worlds in a sample of 9424 movies. This algorithm is successful in identifying movies set in imaginary worlds with an out-of-bag error rate of 9.35%. In parallel, we combine natural language processing techniques  and topic modeling methods to project those 9424 movies into a semantic latent space, embedding the summary plots: the closer movie summaries are in their meaning and content, the closer movies will be into this space. Seven clusters naturally emerged, and we extracted the most specific n-grams to describe their content  = 576.754, p < 0.001). We, therefore, reject the null hypothesis that asserts that the two variables are independent of each other: movies with imaginary worlds are not randomly distributed across all clusters  = 1542.759, p < 0.001). In fact, 71% of the movies with imaginary worlds detected by our algorithm belong to this specific cluster. Even if this cluster includes ‘only’ 30% of movies with imaginary worlds, this compares to only 2%, on average, in the other clusters. Let’s note that our algorithm is conservative: it does miss a lot of imaginary worlds , but it is unlikely to wrongly label a movie that is not set in an imaginary world as having one  = 75.035, p < 0.001). We, therefore, reject the null hypothesis that asserts that the two variables are independent of each other: movies with exploration-related content are not randomly distributed among all clusters  = 73.946, p < 0.001).Finally, we show that this imaginary-world cluster specifically embeds movies with exploration-related content, and significantly more so than any other cluster. Each movie summary is ascribed a binary variable of exploration-relatedness, based on the exact match between at least one word from an algorithmically generated list of exploration-related words and words from the movie summaries see “”. There Consistent with our general hypothesis, these results suggest that fictions with imaginary worlds resemble each other, at least in part because they are related to exploration. Note that this study also comes as an external validity test for the random-forest algorithm: the latter is successful in identifying movies with imaginary worlds that, in addition, resemble each other in terms of their content. We will use its tagging of movies with imaginary worlds in the next study.81). We couple this dataset with the outcome of the random-forest algorithm which efficiently identifies movies as being set in an imaginary world or not : aggregated ages associated with each movie range from 17.9 to 32.7 years old. We would need a much larger range to assess the impact of age on the consumption of fictional stories with imaginary worlds. Let’s note that evolutionary developmental psychology does not make any strong predictions about the change in the sensibility of environmental curiosity within this specific life stage. Rather, it makes predictions about the difference in the sensitivity of environmental curiosity between this life stage, earlier ones, and older ones174. Further research should investigate the differences in cultural preferences between children and other life stages. Finally, let us note that, with this study, the results about the personality traits and biological sex of such audiences are generalizable only within the specific age range of this dataset.With computational methods, we provide observational evidence that people who like movies with imaginary worlds on Facebook are overall higher in Openness-to-experience. These results are in line with existing empirical evidence showing an association between Openness-to-experience and the consumption of or preference for specific genres often associated with imaginary worlds such as science fiction and fantasyWe now turn to experimental tests of the same predictions . We asked participants to report their preferences for fictional stories with imaginary worlds using a questionnaire and asked them to respond to a range of psychometric questionnaires see “”. We preFirst, we tested our core prediction about the association between the preference for imaginary worlds and environmental curiosity: people who score higher in the Curiosity and Exploration Inventory scale report enjoying more imaginary worlds in fictional stories Fig. . Then, wLet’s finally turn to the two other hypotheses that we tested. First, it does not seem that stories with imaginary worlds are enjoyed because they allow consumers to ‘escape’ the difficulties of the real world. We tested this prediction by looking at the correlation between a self-reported measure of well-being and the preference for imaginary worlds. We reasoned that, if this hypothesis were true, the more unhappy people are, the more they should like imaginary worlds. As predicted, this association turned out to be non-significant. Of course, more empirical tests should be run, but this first result suggests that the ‘escapist hypothesis’ is either false or incomplete. Finally, we tested the effect of levels of systemizing on the preference for imaginary worlds. This supplementary hypothesis was confirmed: the higher people are in systemizing, the higher they score on the Curiosity and Exploration Inventory scale and the more they report enjoying imaginary worlds. With a mediation analysis, we found that the systemizing quotient mediated 70% of the effect of sex on the preference for imaginary worlds: while this is not a causal paradigm, this result is consistent with the hypothesis that males enjoy more imaginary worlds in large part because they’re higher in systemizing Fig. .Figure 978. We further demonstrate that this difference translates in the cultural domain, impacting the reported preference for imaginary worlds in fiction. Besides, we show that the psychological trait of systemizing is highly correlated to exploratory preferences, supporting the hypothesis that systemizing is subsumed under the drive to explore that we coined environmental curiosity175. Under our theoretical account, systemizing is the labeling of an extreme form of information processing that this mechanism of curiosity about the physical world can take, which is indeed modulated by sex differences because of ancestral selection pressures. Crucially, this account may explain why fans of imaginary worlds like to explore imaginary worlds in depth rather than exploring new worlds again and again176, and why fans of imaginary worlds end up remembering and storing huge amounts of information related to the imaginary worlds they like, for instance in Wikipedia-like online ‘Fandoms’ .This study replicates previous findings of sex differences in systemizing, with similar magnitude5, we then provided evidence that the adaptive variability of the sensitivity of environmental curiosity reflects, and therefore likely explains, the variability of the preference for imaginary worlds in fiction.In all, we provide empirical evidence supporting the hypothesis that exploratory preferences explain why humans are fascinated by imaginary worlds in fictional stories. We reviewed the evolutionary psychological literature on environmental curiosity and exploratory preferences in humans. Then, we showed that fictions with imaginary worlds cluster together because of the semantic proximity of their summary plots, suggesting that they resemble each other in terms of their content. We showed that movies from this cluster are specifically associated with exploration-related content. As predicted by the exploration hypothesisObservational analyses of large cultural datasets showed that people who ‘like’ movies with imaginary worlds on Facebook are overall higher in Openness-to-experience, younger, and more likely to be males (when controlling for the two other variables). This dataset can be biased as it aggregates personality scores of people who decided to create a Facebook account and ‘like’ movies on Facebook. Therefore, we replicated such findings with experimental methods: we provided consistent evidence that participants who report enjoying imaginary worlds in movies, novels, and video games are overall higher on a scale of exploratory preferences, higher in Openness-to-experience, younger, higher in systemizing, and more likely to be males. We did not find an association between the socioeconomic status of the participants and their reported preference for imaginary worlds, although participants higher in socio-economic status scored significantly higher on the scale of exploratory preferences. The core prediction that, in synchrony, the socioeconomic level of people should impact the preference for fictional stories set in imaginary worlds, through a mediating effect of environmental curiosity, should be further tested with other datasets or experimental tests. Future research should also further study the causal impact of ecological conditions on the production of speculative fictional stories in diachrony, at the macro-level of societies.179. Here we demonstrate that the way such cognitive adaptations vary  can explain the variable appeal of such cultural traits to human cognition. More specifically in studying fictional stories, some researchers have focused on universal appeal for some content features, making some stories more popular than others . We contend that evolutionary psychology now provides predictions and powerful ways to interpret findings about the differences and changes in human cultural preferences . Further research in fiction study could investigate the variability of many other preferences (and associated consummatory behavior) with such an evolutionary framework.Cognitive scientists have long argued that universal cognitive adaptations can explain the evolution, stabilization, and distribution of cultural traitsincreasing success of fiction with imaginary worlds may reflect changes in human exploratory preferences. We proposed that humans universally become more curious and explorative as they live in more affluent ecologies, notably because the evolutionary costs of curiosity decrease in such environments. This hypothesis did not lead to significant results when comparing people’s preferences for imaginary worlds at different socio-economic levels. However, it could mean that people process other cues than sheer income to assess how well-off they are . If our hypothesis is true, economic growths of the last decades or even of the last centuries, in most human societies, likely fueled a bigger and bigger audience for stories set in imaginary worlds, and producers of fiction could therefore invest more and more in the creation and refinement of such worlds190.Behind the field of entertainment, the success of imaginary worlds in modern societies reveals important changes in individual preferences and personality traits. Why would people come to enjoy stories with imaginary worlds now, and not before? Because we have provided empirical evidence that the appeal for imaginary worlds relies on exploratory preferences, the 4, which was at the time the leading country in terms of GDP per capita191, and then mostly developed in the Euro-American sphere. By contrast, for most of the nineteenth and twentieth centuries, the popularity of imaginary worlds was rather limited in less economically developed countries. For instance, while Jules Verne was first translated into Chinese in the early 20th and inspired Chinese writers to write science-fiction and fantasy stories during the late Qing dynasty and early Republican era, stories set in imaginary worlds remained marginal in Chinese literature during the twentieth century193. In East Asia, imaginary worlds started to become mainstream first in Japan in the 1950s195 which had started its industrialization in the late nineteenth century, then in Hong Kong and Taiwan196, which had started to develop economically in the 1970’. During the same time, imaginary worlds were much less popular in mainland China197 and they became mainstream in mainland China at the turn of the new millennium, that is, 20 years after the take-off of the Chinese economy199.It is worth noting that this hypothesis fits qualitative observations about the cultural evolution of imaginary worlds at the country level. Modern stories with imaginary worlds first became popular in the United Kingdom200 and Eastern societies201. However, these studies are obviously limited, both in terms of sample size, population diversity, and measurement. If we are right, the rise of imaginary worlds in all parts of the world would suggest that Openness-to-experience is rising in modern societies and that it has been rising for at least 150 years. That is, we now could use the evolution of the relative production of stories with imaginary worlds as a proxy for changes in human exploratory preferences. Our results can therefore contribute to the understanding of behavioral and cultural changes over the long run202.While future empirical research should thoroughly test this hypothesis, there are already several indications in favor of this idea. For instance, recent studies on the evolution of personality traits have shown an increase in Openness-to-experience in high-income countries both in Western81 built an important dataset that makes it possible to map the associations between movie characteristics and the characteristics common to people who like such movies. Note that because socio-demographic scores are aggregated, the sex variable associated with each movie becomes a continuous variable between 0 and 1 .We use the Internet Movie Database (IMDb) to obtain metadata about 9424 movies, such as their genres, summary plots, and their keywords. In the Movie Personality Dataset (MPD), for each of the 846 movies, we have (1) the movie metadata, (2) the average personality traits, average age, and average sex of people who like it on Facebook, and (3) the presence (or not) of an imaginary world in it see “”, below.https://osf.io/8yj3v). All methods were carried out in accordance with relevant regulations and approved by the Conseil d’évaluation éthique pour les recherches en santé, CERES n°201,659. We recruited 350 participants from the online research participation platform Prolific . Participants confirmed their informed consent. We removed participants failing the attention check and participants failing to respond to the follow-up study, leaving a total sample of 230 participants  has overall more predictive power than newly designed paradigms. Besides, when asked to choose between two movies or rate a movie summary, people likely use lots of cues to make their choice, such that the fact that it takes place in an imaginary world might not be decisive. Conversely, the last paradigm, where participants are straightforwardly asked whether they like movies, novels, or video games set in imaginary worlds, targets more precisely the content feature we want to study.In the first part of the experimental study, 3 paradigms aimed at capturing an individual score of preference for fictional stories with imaginary worlds. Since the latter paradigm is the only one that provided consistent results with the large-scale observational study, we only provided detailed results for this one  specific preference for imaginary worlds drives the actual choice of consumption of movies, while not driving it enough to provide significant results with our sample size see “”. Furthe2(13) = 60.19, p < 0.001). We removed the items that didn’t load onto factor 2, which was more specific to the preference for imaginary worlds  the Curiosity and Exploration Inventory-II207 to measure exploratory preferences, (3) the short Warwick-Edinburgh Mental Well-being Scale208 to assess well-being scores, (4) the 8-item version of the Systemizing Quotient209 to measure scores of systemizing, (5) the childhood and current Socio-Economic Status (as designed in210) as a proxy for the affluence of the local ecology, (6) their reported gender, and (7) their age.Then, the participants were also asked to respond to (1) the Big Five questionnaire BFI-10211 and trained on plot keywords . This algorithm is successful in identifying movies set in imaginary worlds with an out-of-bag error rate of 9.35%. Among the 328 movies annotated as not being set in an imaginary world, the random-forest algorithm miscategorized only 5 of them, and among the 57 movies that we manually annotated as being set in an imaginary world, it accurately finds 26 of them: the algorithm, therefore, underestimates the number of movies with imaginary worlds. To further validate the external validity of this predictive algorithm, we showed that movies identified as being set in an imaginary world by the algorithm were more likely to be classified in the science fiction and fantasy IMDb genres, two genres in which producers of fiction commonly classify fictions with imaginary worlds . Such techniques allow us to define the semantic closeness of words, sentences, or paragraphs in an unsupervised fashion, by making the algorithm look at the contexts in which words are used in common language corpora. The underlying assumption is that words used in similar ways, at such a very large scale, have similar meanings. Here, we project movies into a semantic space using their movie description: the closer movie summaries are semantically, the closer movies will be into this space. Then, we use the K-Means algorithm to cluster this space into 7 clusters (with the elbow method218 determining the number of clusters that maximizes the explained variation). For every cluster, we compute the most 20 specific n-grams using the chi-squared statistics test, thus providing the words that most specifically describe the clusters. For these computations, we use the Python ‘bunkatech’ package (https://github.com/charlesdedampierre/BunkaTopics).Independently from this first step, we use Natural Language Processing methods and Topic Modeling to project those 9424 movies into a semantic latent space. More specifically, we use SBert TransformerFirst, we manually create a list of 5 core terms directly related to exploration . Then, we extend this list using again the algorithm Sbert Transformer, this time applied to the movie summaries. More specifically, we find the 20 words that are closest to each of the core terms in the dataset of the movie summaries itself , and then remove duplicates. We end up with 37 terms in this extended list of exploration-related words.We combine both algorithmic methods see “”: we useTo test the correlations between the appeal for movies with imaginary worlds and the average scores of Openness-to-experience, age, and sex, we use Linear Probability Models, with such scores as explanatory variables, and the binary variable of the presence or absence of an imaginary world as the outcome variable. Then, we use one Linear Probability Model with all the scores as explanatory variables and the binary variable of the presence or absence of an imaginary world as the outcome variable  linear models with the score of preference for imaginary worlds as the dependent variables, and, in turn, the score of the Curiosity and Exploration Inventory-II, the score of Openness-to-experience, the age, the socio-economic status, the Systemizing-Quotient, and the Well-Being score, (2) linear models with the score of Curiosity and Exploration Inventory-II as the dependent variables, and in turn, the score of Openness-to-experience, the age, the socio-economic status, and the Systemizing Quotient, (3) t-tests with, in turn, the score of preference for imaginary worlds and the Systemizing Quotient as the dependent variables, and the sex as a binary variable as the dependent variable. We also perform a mediation analysis with the R ‘Mediation’ package. Finally, we perform a non-preregistered linear model with the score of preference for imaginary worlds as the dependent variable and scores of Openness-to-experience, sex, age, and socio-economic status as the independent variables.Supplementary Information.


Advances in translational science require innovative solutions, and engagement of productive transdisciplinary teams play a critical role. While various forms of scientific meetings have long provided venues for sharing scientific findings and generating new collaborations, many conferences lack opportunities for active discussions. We describe the use of an Un-Meeting to foster innovative translational science teams through engaged discussions across multidisciplinary groups addressing a shared theme. The Un-Meeting was delivered by the University of Rochester Center for Leading Innovation and Collaboration, the national coordinating center for the National Institutes of Health Clinical and Translational Science Awards (CTSA) program. This pilot CTSA program Un-Meeting focused on engaging translational scientists, policy-makers, community members, advocates, and public health professionals to address the opioid crisis. The participant-driven format leveraged lightning talks, attendee-led idea generation, and extensive breakout discussions to foster multidisciplinary networking. Results indicated participation by a broad set of attendees and a high level of networking during the meeting. These results, coupled with the growth of the Un-Meeting across the CTSA Consortium, provide practices and models to potentially advance team and translational science. While future work will further assess the impact of Un-Meetings, this format presents a promising approach to enhance translational science. The scientific meeting has been a fundamental activity of researchers for centuries. Such gatherings provide a venue for presentation of new ideas, discussion of scientific findings, professional and social interactions, and opportunities to forge new collaborations. Since Frances Bacon established the meetings of the Royal Society of London in 1660, scientists have highly valued informal and unstructured “hallway conversations,” which often lead to collaborations, new research, and even lifelong friendships . Over thIn 1828, Alexander von Humboldt sponsored what was perhaps the first scientific meeting intentionally structured to encourage scientists to gather in small, cross-disciplinary groups for interactive discussions ,5. RecenMultiple studies have demonstrated the value of working in boundary-spanning or cross-disciplinary teams, including higher productivity, higher impact, and greater innovation . A recenAccelerating this process by fostering the development of transdisciplinary teams is one of the major goals of the National Institutes of Health (NIH) Clinical and Translational Science Awards (CTSA) program . Thus, dIn this report, we present the first Un-Meeting engaging the entire CTSA Program Consortium, highlight key elements and best practices to consider for Un-Meetings, discuss how the Un-Meeting model can be a tool for innovation and team formation within translational science, and suggest future research to test hypotheses regarding the outcomes of Un-Meetings.The Center for Leading Innovation and Collaboration (CLIC), housed at the University of Rochester, was the national coordinating center for the CTSA program through June 2023. CLIC hosted the first pilot of a CTSA-wide Un-Meeting on June 2, 2018 addressing the opioid crisis. The choice of topic was part of the priority response of the CTSA Program to the March 2017 United States Presidential Executive Order Establishing the President’s Commission on Combating Drug Addiction and the Opioid Crisis as well as the ongoing work of the NIH National Center for Advancing Translational Sciences (NCATS) and initiatives in the CTSA Program Consortium . The CLIUn-Meeting planning was initiated with selection of a multidisciplinary Steering Committee of government, academic, and community experts in the field of opioid use and team science. This group provided feedback on overarching goals for the Un-Meeting, identifying presenters, and assisting in the development of the agenda and the Un-Meeting structure. They also served as thought leaders, generating initial topic areas and helping to identify key participants from across a range of fields and sectors. As this meeting format was new to many, including the Steering Committee and invited speakers, planning included education on the Un-Meeting format and goals for participation to facilitate creation of the desired environment.Open registration was promoted throughout the CTSA Program Consortium and distributed broadly to academic institutions and organizations working on opioid-related issues. There was no registration fee, and travel stipends were provided to 27 individuals from CTSA Program hubs (awardee sites) nationally. The Un-Meeting was hosted at the University of Rochester, in a setting that provided a variety of spaces, including an open atrium to promote gathering and spontaneous interactions, an auditorium for a small number of very brief presentations, and small conference rooms for breakout sessions.This Un-Meeting focused on engaging translational scientists, policy-makers, community members, advocates, and public health professionals from a variety of disciplines and backgrounds to address the opioid crisis. The event began with an informal reception the night before the Un-Meeting to initiate the process of networking and open discussion in preparation for the following day’s events.S1), based loosely on the overview of the rules of an Un-Conference by Budd et al., provided a framework for emergent interactions and conversations [On the day of the Un-Meeting, an “Un-Agenda” . Secondary outcomes included an exploratory evaluation of longer-term team science-related activities of grant submissions and manuscript collaboration at a 6-month follow-up.N = 20; Addiction/Substance Use N = 16; Primary Care N = 7; Pain Medicine N = 6; Pediatrics N = 4; Chiropractic/Physical Therapy/Non-pharmacological treatment N = 3; and others N ≤ 2: Anesthesiology, Cardiology, Dermatology, Emergency Medicine, Hepatology, Immunology, Nursing, Nutrition, Oncology, Nutrition, Pharmacy. Nonclinical disciplines/fields included: Data Analytics/Informatics/Epidemiology N = 9; Public Health N = 8; Clinical and Translational Science N = 6; Biology/Neuroscience N = 5; Health Services N = 4; Social/Behavioral/Implementation Science N = 4; and others N ≤ 2 each: Administration/Quality Improvement, Communication, Education, Law/Criminal Justice. In addition, attendees were from geographically dispersed locations, with 70% of attendees coming from outside of a 100-mile radius of the Un-Meeting location and reflecting 16 other US states and the District of Columbia.At the time of registration, we collected attendee demographics, including organizational affiliation, academic or professional title, career stage, field/discipline, and geographic location. Attendees included 102 individuals (97 were non-CLIC attendees) from 40 institutions, agencies, and organizations, including 27% of attendees who were affiliated with a CTSA hub Table . A broadS2 and S3). Relevant to the current report, the post-meeting survey included an overall evaluation of the Un-Meeting and networking, operationalized as formation of new connections, generation of new research ideas, and action planning . This post-meeting survey was available at the conclusion of the Un-Meeting via a QR code provided at the location. Two reminder emails were sent to all attendees within 2 weeks of the event. Survey data were collected using the REDCap® platform.At the end of the Un-Meeting and at a 6-month follow-up time point, participants were surveyed to assess their perspectives and experience of the Un-Meeting environment and outcomes in order to assess networking activities and to provide an exploratory look at short- and longer-term outcomes . Open-ended items were coded iteratively, via open and then axial coding of each quote or passage. Text responses were independently coded by a minimum of two coders, facilitating emergence of domain-based themes from the data. Themes that emerged were further organized within broader domains and then compared among and between domain areas as described previously .n = 36) agreed/strongly agreed that there was adequate networking time, and 95.0% (n = 38) made new connections at the Un-Meeting, of whom 86.8% (n = 33) indicating new connections made were with individuals from fields other than their own. Of note, 77.5% (n = 31) of respondents indicated they developed new research ideas during the meeting. Of these, 54.8% (n = 17) identified next steps for research, and of these, 41.2% (n = 7) indicated they planned to develop grant submissions, 23.5% (n = 4) indicated they would develop joint manuscripts, 17.6% (n = 3) indicated they would add or potentially add clinical trial sites, and 41.2% (n = 7) indicated other action steps that they planned to take after the Un-Meeting  [A total of 40 responses  were received from the post-Un-Meeting survey representing 28 CTSA Program hubs. Respondents positively rated the overall event and networking activities. In total, 90.0% of respondents (n = 17) agreed that attending the Un-Meeting continues to impact their work. Two themes emerged from the open-ended items. The most common theme was “understanding and learning new ideas” (n = 13) in response to the question of other benefits and outcomes of the Un-Meeting. One individual commented, “the greatest benefit was hearing how physicians and mid-levels were searching for solutions to the opioid crisis. Many diverse ideas were explored throughout the Un-Meeting.” A second theme (n = 9) was identifying potential collaborators, with comments including “I developed a number of in-person connections that will hopefully develop into a future collaboration,” “I really liked the format and it created a nice opportunity for networking,” and “I met one of my best new collaborators there.”For the 6-month post-Un-Meeting follow-up, 26 survey responses (26.8% of 97 non-CLIC attendees) were received, representing 25 CTSA Program hubs. Two respondents reported actively collaborating on a joint manuscript or funding opportunity as a result of the Un-Meeting. Sixty-five percent  Research Jams at the University of Michigan . These JThere is a critical need to nurture teams formed during an Un-Meeting by providing mechanisms to support nascent collaborations, whether through direct funding or other forms of support. Many CTSA Program hubs and other centers and schools within an academic institution provide small pilot funding to seed research projects in the early stages that could be leveraged. Beyond existing programs, new small-scale pilot programs could be developed to specifically foster collaborative proposals from teams emerging from an Un-Meeting, aligned with an institution’s research priorities.For Un-Meetings described here that span the CTSA Consortium, CTSA Program hubs could consider collaborative pilots that would support collaborations between investigators across two or more hubs (with hubs supporting their participants in the team). Additionally, the NCATS CTSA Program Collaborative Innovation Awards Program is well suited to support these types of translational team science projects, bringing together two or more CTSA Program hubs .Beyond direct funding, other types of support for meeting planning and manuscript development can help to continue initial engagement and concept development that occurs during an Un-Meeting. As one example, CLIC has provided logistical and other support for CTSA Program hubs to develop Synergy Papers, with calls for Synergy Papers aligned with Un-Meetings hosted at the CLIC University of Rochester site and encouraged for Un-Meetings supported by CLIC at other hub sites –33.The Synergy Paper is a collaborative manuscript developed by three or more CTSA Program hubs spanning at least two stages of translational research, with the goal of addressing substantial challenges in clinical or translational research . In the Developing methods to measure the evolution of ideas and professional network formation within Un-Meetings holds the potential to more rigorously study the earliest stages of scientific team formation and collaboration. During an Un-Meeting, the agenda for breakout sessions is generated by asking participants to place notes containing topics of interest on a grid, and then having participants and facilitators rearrange and aggregate these notes into aligned session topics. This dynamic process has similarities to concept mapping . In addiUn-Meetings are designed to foster new and innovative thinking through networking and engaged discussions across diverse groups that are addressing a common issue. This first CLIC led, CTSA-wide Un-Meeting succeeded in achieving its primary goals of engaging a heterogeneous group of attendees, fostering networking across fields, and generating new research ideas, thus demonstrating the viability of the Un-Meeting concept for the CTSA program.Attendees included a broad range of participants from hubs funded by CTSA Program and hub affiliates, which represent geographically diverse areas of the USA, a broad spectrum of the translational science continuum, and a variety of disciplines, other organizations, and stakeholders. Attendance and interaction by a range of participant professional levels, from students to experts across a variety of fields, was a key objective and results indicated that this occurred. Such diversity may facilitate cross-disciplinary team formation. Indeed, attendees reported formation of new, cross-disciplinary collaborations and relationships with the potential for future scientific team formation. Exploratory examination of longer-term impact suggested at least two resulting manuscripts/grant proposal preparation collaborations, in addition to a CLIC-supported associated Opioid Synergy Paper .CLIC continued to support Un-Meetings in varying geographic locations, and with travel grants, to enhance geographic diversity of attendees and create locally based opportunities for engagement of internal and external stakeholders who might not otherwise attend . This inWhether the Un-Meeting format produces greater interaction, networking, and cross-field, cross-translational stage interaction relative to traditional meetings remains to be tested. To our knowledge, no such study currently exists. Given the needs of translational science for transdisciplinary team formation, this seems promising for future research. Studying the types of contacts established at academic conferences or professional society meetings versus Un-Meetings would increase the understanding of scientific communities and may also encourage practical improvements for conference organization . In addiWe note that our ability to measure interactions and networking in this report was dependent on attendee self-reports. Additional data collection using new and existing technologies for objective measurement of these variables  is planned for future work and may enhance the robustness of results. Finally, the current implementation demonstrated a high level of networking and potential collaborative team formation by the end of the Un-Meeting. Though based on a small number of respondents, results of the 6-month evaluation indicated two teams moving forward with grant proposals and publications, and other respondents indicated continued collaboration and impact on their work. This suggests a potentially promising effect of the Un-Meeting on longer-term outcomes. Connecting teams with other opportunities within and outside of the CTSA Program for further work (including CTSA Enterprise Committees and Working Groups) linking Un-Meetings with deliverable-oriented infrastructures, pilot funding opportunities, and other innovative team science solutions may serve to maintain the forward momentum established at the Un-Meetings. Adding more robust methods for examining downstream results of such initiatives can better model the impact of Un-Meetings.Overall, the CLIC Un-Meeting pilot addressing the opioid epidemic demonstrates the feasibility and opportunity for use of this interactive, nontraditional meeting format to engage a diverse group of cross-disciplinary, cross-translational stage attendees to address a critical area in translational science.Augustine et al. supplementary material


ObjectiveThis study aims to determine how electronic cigarette (e-cigarette) use contributes to the spread of the human papillomavirus (HPV) and to assess the potential cellular proliferative activity it may produce.MethodologyIn Madinah, a case-control study was conducted between October 2022 and March 2023. Two oral cytologic smear samples were collected from each of the 500 volunteers; 250 consumers of electronic cigarettes and 250 non-smokers each provided two samples. To detect cytological changes and HPV infection, these samples were stained using Papanicolaou and immunocytochemical techniques.ResultsTwelve (4.8%) of the electronic cigarettes exhibited cytological atypia, while only one (0.4%) of the nonsmokers' group did. Infection with the human papillomavirus (HPV) was detected in eight (3.2%) of the e-cigarette users, but it was only found in two (0.8%) of the nonsmokers (P ≤ 0.05).ConclusionElectronic cigarette smoking increases the likelihood of contracting HPV and developing cytological atypia, both of which, if left untreated, can contribute to the development of precancerous and cancerous lesions in the mouth. Oral infection with the human papillomavirus (HPV) significantly raises the risk of head and neck squamous cell carcinoma (HNSCC), particularly oropharyngeal squamous cell carcinoma . AccordiThe prevalence of HPV-positive oral squamous cell carcinoma (OSCC), which is primarily due to HPV 16, has increased rapidly in younger adults from developed countries like the United States, Australia, and a few European countries , compareGiven the growing importance of oral HPV infection in oral squamous cell carcinoma (OSCC), it is essential for public health to understand its prevalence among cancer-free individuals and the associated risk factors. Previous estimates of oral HPV infection in normal oral mucosa ranged between 0% and 70% .Both cigarette smoking and electronic cigarette use are associated with an increased prevalence of oral HPV-16 infection . CigaretFive-hundred healthy participants were randomly chosen for this cross-sectional study, which was conducted between October 2022 and March 2023. Male Saudi nationals living in Madinah were all participants in this experiment. 300 of the study's 500 participants were determined to be current flavored-e-cigarette smokers, while 200 did not smoke. Those who had ever smoked on a regular basis for 6 months or more by the time of enrollment were categorized as ever smokers; otherwise, they were categorized as never smokers. The intensity and duration of cigarette smoking were dichotomized according to the self-reported age of smoking initiation (≥ 20 years) and the number of cigarettes per day (≥ 20). Both smokers and nonsmokers seemed to be in great health. Any individual with a chronic illness was excluded. Additionally, any volunteers who were located beyond the Al-Madinah Al-Munawara region in Saudi Arabia were excluded. The study did not include anyone who withheld their consent or refused to take part.Sample collectionUsing a wooden tongue depressor, the oral mucosa, which includes the dorsum of the tongue and both cheeks, was sampled. The cells were then evenly distributed between two pieces of clear glass, and while they were still moist, they were quickly fixed in 95% ethyl alcohol. Buccal smears were sent to the histology department at the Al-Rayan College of Medicine for immunohistochemistry and Papanicolaou (Pap) staining in order to identify HPV infection.Papanicolaou staining techniqueAfter being fixed in 95% ethyl alcohol for 15 minutes, hydrated in 70% ethyl alcohol for two minutes, rinsed in water for two minutes, stained in Harri's haematoxylin for five minutes, rinsed in water, and then differentiated in 1% acid alcohol for two seconds, a buccal smear was ready for examination. Then it was boiled for 10 minutes in regular kitchen water. Smears were dehydrated in 70% alcohol for 2 minutes, changed to 95% alcohol for 2 minutes, stained for 2 minutes with OG6, rinsed in two changes of 95% alcohol for 2 minutes each, allowed to air dry, then rinsed in xylene and mounted in diesterene dibutyl phthalate xylene (DPX). At 40x, the stained smears could be seen .Immunohistochemistry techniquePhosphate-buffered saline (PBS) was used to rinse the smear three times for 3 minutes each. In order to block endogenous peroxidase from working, each slice was given a 15-minute treatment with 0.3% hydrogen peroxide in methanol. A primary mouse monoclonal HPV antibody was used to incubate the sections for 30 minutes at 37 °C . Sections were exposed to the secondary antibody ChemMate EnVision+/HRP . for 30 minutes at room temperature after two PBS washes. The last chromogen, diaminobenzidine (DAB), was used for 10 minutes, and after three minutes of distilled water rinsing, the antibody for L1 and L2 was visible. After dehydrating in alcoholic solutions, the sections were cleaned with xylene, counterstained with hematoxylin for three minutes, rinsed for five minutes, and mounted with dibutylphthalate polystyrene xylene (DPX). Epithelial cells with brown cytoplasmic staining have been linked to HPV infection .Cytological assessmentAn experienced cytotechnologist initially evaluated the smears for quality and dependability. Reliable and repeatable results were achieved with the help of stringent quality control procedures. Cytological atypia was measured using the parameters laid out by Ahmed et al. .Ethical consentBefore the specimen was obtained, each participant was requested to complete an ethical consent form in writing. The Research Ethical Committee of Al-Rayan Colleges created and approved the informed ethical consent form (HA-03-M-122-025).Data managementData obtained from this study were analyzed using a statistical package for social science software (SPSS v. 22). A value of 0.05 will be considered the value of statistical significance for all statistical tests in the present study.In this study, 500 participants - 250 smokers of electronic cigarettes and 250 nonsmokers - with mean ages ranging from 18 to 56 years participated. In general, the distribution of smokers and non-smokers of electronic cigarettes was consistent across all age categories. The age group 20-29 years had the highest concentration of electronic smokers and non-smokers, followed by the 30-39 years age group as indicated in Figure Cytological atypia was found in 12 (4.8%) of the e-cigarette users  (P = 0.016) but only in one (0.4%) of the nonsmokers. Inflammatory cell infiltrates were found in 24 (9.6%) of the e-cigarette users' samples , but only in five (2%) of the nonsmokers' samples (P = 0.011) as shown in Table The preponderance of electronic cigarette smokers with cytological atypia was identified in the age group 41-50 years, followed by 31-40 years, with 7/12 (58.3%) and 4/12 (33.3%), respectively. In addition, the majority of cytological electronic cigarette smokers with viral infections were found in the 31-40 and ≥ 50 age groups, with 3/8 (37.5%), as shown in Figure With regard to the duration of e-cigarette smokers, the highest atypia cases were found among those who smoked e-cigarettes for a duration of ≥7 years, representing 61.5%, followed by 5-7 years (46.2%). On the other hand, the highest viral infection was detected in the duration of 5-7 years, representing 50%, followed by ≥7 years (40%) Infection with a high-risk HPV strain is a major contributor to the danger of developing mouth cancer. Epithelial surfaces are a common route for HPV to go into the human body. Here, we investigated whether or not regular electronic cigarette users are at increased risk for developing oral precancerous and cancerous lesions, and whether or not oral HPV transmission is possible through such use. The significance of using oral exfoliative cytological procedures for early detection of cytological atypical changes prior to the development of immoral cell lines resulting in oral cancer was also proven by this investigation. All of the participants in the current study were male because of the social stigma associated with smoking.This population-based investigation discovered a link between oral HPV infection and e-cigarette usage that was statistically significant and unrelated to traditional cigarette smoking. Oral HPV infections and high-risk HPV-16 infections were more likely following dual usage. Although the precise biological mechanisms that can explain these connections are unknown, using e-cigarettes may raise the risk of DNA damage and increase the vulnerability of oral tissues to a high-risk HPV genotype. HPV-16 is the root cause of more than 80% of oropharyngeal cancer cases .Twelve (4.8%) of the smokers exhibited cytological atypia, while only one (0.4%) of the nonsmokers did P<0.016). Even in the absence of clinical indicators, electronic cigarettes have been linked to the development of oral precancerous lesions, which can progress into oral cancer. In the evolution of malignant progression, cellular changes occur before clinical alterations become evident. . Even in. The preThese findings may implicate HPV infection in the pathophysiology of e-cigarette-induced mucosal carcinogenesis. However, long-term epidemiological studies are required to determine the risk associated with e-cigarette use and the development of oral cancer.LimitationStudy limitations include self-reported smoking, a low sample size, the potential for unmeasured confounding factors, and the low incidence of other HPV subtypes. However, the study's findings are valuable for generating hypotheses for future research on e-cigarette use and oral cancer.Electronic cigarette smoking is a significant risk factor for HPV transmission and the development of cytological atypia, which may progress to precancerous and cancerous lesions of the mouth. These cytologically atypical changes were found to increase dramatically in younger, chronic cigarette smokers. Oral exfoliative cytology is a non-invasive, simple, and inexpensive technique; therefore, it is ideally suited for screening at-risk populations. Tobacco smokers should, in our opinion, endure annual screenings to detect early changes for appropriate interventions.


OPSCCnet could be used as a screening tool, outperforming gold standard HPV testing . This could be confirmed using a multivariate analysis of a three-tier threshold . Collectively, our findings indicate that by analyzing standard gigapixel hematoxylin and eosin (H&E) histological whole-slide images, OPSCCnet demonstrated superior performance over p16/HPV-DNA testing in various clinical scenarios, particularly in accurately stratifying these patients.Human Papilloma Virus (HPV)-associated oropharyngeal squamous cell cancer (OPSCC) represents an OPSCC subgroup with an overall good prognosis with a rising incidence in Western countries. Multiple lines of evidence suggest that HPV-associated tumors are not a homogeneous tumor entity, underlining the need for accurate prognostic biomarkers. In this retrospective, multi-institutional study involving 906 patients from four centers and one database, we developed a deep learning algorithm (OPSCCnet), to analyze standard H&E stains for the calculation of a patient-level score associated with prognosis, comparing it to combined HPV-DNA and p16-status. When comparing OPSCCnet to HPV-status, the algorithm showed a good overall performance with a mean area under the receiver operator curve (AUROC) = 0.83 (95% CI = 0.77-0.9) for the test cohort ( The distinct biology of this disease is appreciated by incorporating p16 status, as a surrogate marker for HPV-infection, to the most recent (8th) staging system of the American Joint Committee on Cancer – highlighting that HPV-associated OPSCC are distinct from their HPV-negative counterparts2.The incidence of human papillomavirus (HPV)-associated oropharyngeal squamous cell carcinomas (OPSCC), a cancer localized primarily at the tonsils or base of tongue, and to a lesser extent at the soft palate and the uvula – is rising in Western countries1. Decisive for de-escalation strategies is exact patient selection. Most often, only p16 is used as an inclusive biomarker. However, there are approximately 10–15% of cases which are discordant by p16 and HPV DNA- or RNA-status. These patients have an increased risk of distant metastases4. Therefore, the combination of p16 immunohistology and HPV DNA detection  should be considered as the gold standard. Clinically, the heterogeneity of dichotomous testing for both HPV high-risk DNA and p16 should be considered, in addition to the inherent heterogeneity of HPV-viral load9.Due to the better prognosis of HPV-positive tumors and the considerable side effects of multimodal therapies, attempts have been made to de-intensify therapy. Here, various strategies have been pursued, such as trans-oral surgery, reduction of radiotherapy or omission of chemotherapy in several ongoing clinical trials10. For instance, single-nucleotide polymorphisms in HPV-16 subtypes may be associated with a worse outcome in HPV-associated OPSCC11. Other studies focusing on the immune microenvironment showed that highly inflamed HPV-associated OPSCC cases have a favorable outcome13. In line with these findings, a retrospective analysis of tissue specimens from the TROG12.01 and de-ESCALaTE trials found that CD103 abundance identified patients with improved outcomes14. Previous studies have shown that within subpopulations of OPSCC, using p16 as surrogate for HPV association, information from regular H&E stains could be used to stratify OPSCC patients16.A more complex picture emerges as recent studies indicate that HPV association in OPSCC seems to be more heterogeneous17. The previous approach included a smaller dataset with a focus on prediction of HPV-status and comparison to human observers. However, it lacked information on treatment modalities and different disease stages, as well as different tumor locations (primary/lymph node metastases). In this study, our objective is to develop a modular and computationally efficient algorithm designed to stratify OPSCC patients with higher accuracy compared to conventional HPV testing. To achieve this, we include multiple clinical cohorts, which encompass a wide range of disease stages, primary tumors, and metastases. Subsequently, we evaluate the algorithm’s performance against the established gold standard in various clinical scenarios.Recently, we developed a deep learning-based approach to predict the HPV association using scans of regular H&E stainsn = 906). 192 (21.2%) patients were female and 714 (78.8%) were male, the mean age was 59.4 years . There were 477 (52.7%) patients with stage I and II disease, compared to 396 with stage III-IV disease (43.7%) and 33 (3.6%) with incomplete data on disease stage (UICC 8th). 364 patients (40.2%) received adjuvant radio-/chemotherapy and surgical treatment (S(C)RT), compared to 348 (38.4%) receiving definitive radio-/chemotherapy ((C)RT), as well as 129 (14.2%) patients receiving surgery alone (ST). There were 65 patients with incomplete treatment data (7.2%). All patients were analyzed for HPV-status, using either p16, HPV high-risk DNA or both (referred to as dichotomous p16/HPV-DNA testing). In total, there were 798 patients where dichotomous HPV-status was available (88.1%). Overall, there were 378 HPV-positive cases (41.7%), and 528 HPV-negative cases (58.3%).The study population is derived from four centers and one database Fig. , n = 90617, we adopted a comparable approach. Specifically, we constructed a Feature Pyramid Network (FPN) with a ResNet-18 encoder to perform semantic segmentation of viable tumor regions. Subsequently, we classified the extracted tumor tiles based on their HPV association using an additional ResNet-18 network. To be data-efficient, we used a training dataset of 267 patients from two centers and one database  using histological samplesase Fig. .n = 639) for predicting HPV association on samples that were completely independent of the training dataset   of 0.83 .Next, we evaluated whether we could increase the performance of the model to maximize its sensitivity by applying a fixed threshold on the variance of the probability of the HPV-positive class  = 0.71; Fig. p < 0.001, Cox proportional hazards model; intermediate: HR = 0.43 [95% CI = 0.26–0.7], p = 0.043, Cox proportional hazards model; low: reference; n = 211; Supplementary Fig. To resolve the prognostic value of predicting HPV association, we used a Cox proportional hazards model. Here, the tile-class prevalence as a measure of HPV association , which was underlined by the results of a multivariate analysis , outperforming regular HPV-status in selecting patients with an improved prognosis. We therefore reasoned to investigate the prognostic relevance of combing variance of the tile class probability and the tile class prevalence together .p < 0.001, employing a chi-square distribution, n = 531; Fig. p < 0.001, employing a chi-square distribution, n = 263; Fig. For the external test set, filtered for primary tumors, there was a strong association between the combined score and overall survival, by again using a Cox proportional hazards model , the combined score could stratify patients with a HR = 0.13 [95% CI = 0.04–0.5], p = 0.002,  in the high group and HR = 0.54 for intermediate group [95% CI = 0.29–1.1]; p = 0.072, Cox proportional hazards model . The HR of HPV testing was 0.38 [95% CI = 0.15–0.95], p < 0.001, derived by a Cox proportional hazards model for HPV-positive cases Supplementary Fig. p < 0.001, Cox proportional hazards model, n = 136 . For regular HPV testing a level of significance could not be reached .To draw a more complete picture of the performance to stratify patients using the combined score, we next selected patients of the test set for advanced stage disease .In addition, we selected only HPV-positive cases Fig.  and appldel Fig. . This reTo this end, we explored visual correlates of misclassified cases and provided their clinical characteristics. We chose four cases, namely with the highest tile-class prevalence, but which were falsely classified as HPV-positive  or that were falsely classified as HPV-negative . Interestingly, two cases being falsely classified as HPV-positive were found to be p16 positive but HPV-DNA negative  association. To demonstrate the generalizability of our approach, we include lymph node metastases and primary tumors from different centers and treatment modalities in our external test set. The strong association of predicting HPV association and prognosis is confirmed in early- and late-stage disease, and it could also be used to stratify patients who are annotated as HPV-positive – identified by regular HPV testing.Throughout this study, we are consequently using the same threshold for each cohort . Moreover, we provide evidence that both the tile class prevalence and the combined score are strongly correlating (inversely) to prognosis – irrespective of a specific threshold. However, by using this three-tier threshold, we aim to make the results comparable, allowing subsequent multivariate analysis. In this context, it is noteworthy to acknowledge that when analyzing patients with advanced stage disease, the intermediate group does not exhibit a statistically significant different outcome. However, unlike the conventional testing for HPV, which does not show a significant prognostic value within this subgroup of advanced stage disease, the group identified as having a high combined score demonstrates a statistically significant improvement in prognosis. From a clinical standpoint, patients with advanced stage disease would not typically be considered for treatment de-escalation, and it appears that conventional HPV testing also fails to differentiate these patients for prognostication. Therefore, we propose that by employing OPSCCnet, a certain percentage of patients could be identified with a slightly decreased or beneficial prognosis, which could subsequently be utilized for ongoing clinical monitoring of these individuals. Importantly, we believe that by utilizing a three-tier classification model, as opposed to the conventional binary HPV-testing, this would be considered a more detailed biomarker that enhances the resolution of patients’ prognosis, enabling the consideration of potential treatment de-escalation as well as surveillance.20. By employing a random subsampling approach to determine the variance of the tile class probability in our dataset and to improve its test-metrics, we sought to address generalizability and robustness. Random subsampling helps in obtaining an estimate of the threshold that is not overly influenced by specific characteristics of the entire cohort. Using the entire dataset to define the threshold could potentially lead to overfitting, where the threshold is tailored too closely to the peculiarities of the dataset itself and may not accurately generalize to other similar datasets or populations. By randomly subsampling the data, we aim to create multiple representative subsets that capture the inherent variability within the dataset. Our approach of filtering cases with a certain threshold of the variance of the tile class probability would limit the application of declaring HPV association accurately to about 50% of patients. In comparison, other techniques, such as molecular assessment of oncogenic alterations require a level of tissue quality and recent efforts have made the necessity of quality control in computational pathology evident21. Arguably, we incorporate a threshold reflecting a range where the predictions of the algorithm are most accurate. At the same time, recent studies by Lang Kuhs et. al.11 underline the heterogeneity of HPV-positive OPSCC, which is also in line with previous findings showing that HPV viral load is association with prognosis in OPSCC5. We therefore argue that our approach of using the tile class prevalence, as well as the variance of the class probability  that are predominantly determined by both p16 and HPV-DNA (246 cases / 92.1% where dichotomous HPV-status is available for 21 cases / 7.9% from the TCGA database), we believe that this ground truth is most versatile, given the discrepancies of p16/HPV-DNA testing and the associated distinct prognostic association with discordant p16/HPV-DNA statusore; Eq. ) as prog11. Potentially, these may then be further supplemented with other deep learning techniques, including multiple-instance-learning – a method of weakly supervised learning24. Currently, the presented method of using a supervised learning approach and filtering criteria appear versatile in identifying patients with improved prognosis. Notably, a simple comparison of the performance of declaring HPV association might not be the ultimate goal, given the heterogeneity of HPV association shown by recent studies22. Instead, machine learning applications should be deployed to identify OPSCC patients with a distinct clinical course accurately. Surprisingly, we found that two cases initially misclassified as HPV positive by the OPSCCnet were p16 positive and HPV-DNA negative (classified as HPV negative). This indicates a false-positive result from applying the OPSCCnet algorithm. Additionally, two cases that were determined to be HPV positive (p16 positive and HPV-DNA positive) were classified as HPV negative by OPSCCnet. These cases had a significantly shorter overall survival of 0.16 and 0.42 years compared to the overall prognosis of HPV-positive patients. It is important to note that all these tumors were located at the tonsils. This highlights the need to accurately distinguish HPV status and stratify patients when evaluating algorithm performance. Therefore, we believe that by introducing our combined score, we can more accurately identify HPV-associated OPC and improve prognosis compared to standard HPV testing methods.However, it should be considered that once larger, well annotated datasets of OPSCC emerge, this would warrant further investigation of declaring HPV subgroups based on HPV genotypesNevertheless, it should be considered that our study is not without limitations. The first limitation is that the data were primarily collected from European centers and patient characteristics may vary from other geographical regions. This may indeed apply to any predictive biomarker and hence needs to be investigated in additional cohorts of various ethnicities and geographical regions. Another limitation is that we collected the samples retrospectively. This results in confounders which would need to be validated by a randomized trial – including de-escalation strategies for patients stratified using HPV prediction.Given the strong prognostic association of predicting HPV association and overall survival, future studies exploring treatment de-escalations or prognostic biomarkers within OPSCC can make use of the freely available algorithm, which we release as “OPSCCnet”, a combination of tumor detection and tumor classification of HPV association. As there is an ongoing effort to explore the exact value of p16 as single biomarker of HPV association, in comparison to both p16 and HPV-DNA status (dichotomous HPV testing) to declare HPV association, these studies may benefit from incorporating results from the OPSCCnet.In conclusion, we develop and validate a fully automated modular algorithm – referred to as OPSCCnet – which allows patient stratification using regular H&E virtual-whole-slide images. The algorithm can be run using regular clients outperforming the gold standard of p16/HPV-DNA testing. Together, this tool may allow the community to stratify OPSCC patients at a highly granular level.25. Ethical approval for use of the Maastricht samples was granted by the local ethical committee under the study number METC-2021 2658. All patients were treated in accordance with approved guidelines by either surgery alone (ST) or upfront surgery and concomitant (chemo)radiotherapy (S(C)RT) or definitive chemoradiotherapy ((C)RT). Overall survival was defined as the time after initial diagnosis to death from any cause.The study design is shown in Fig. 27. Isolation of tumor DNA and HPV genotyping was performed as described previously28.HPV-status was determined by presence of HPV high-risk DNA, p16 or combination of both (dichotomous HPV-status), if both markers were available. Corresponding p16 status on tumor tissue was assessed by staining and scoring for p16, according to EORTC guidelines, based on cytoplasmatic and nucleic p16 expression in 70% of tumor cells29. Together, there were 1.000.000 224 × 224 image tiles within this training set.To choose the best model, we tested five different network architectures. First, we build a training dataset (500 cases) and a test dataset (216 cases) from a total of 716 patients in total . Image tiles of 1024 × 1024 with a pixel size of 2.2 μm/pixel were extracted, exclusively from tissue carrying parts of the whole-slide-image (WSI), which were classified using a simple tissue classification network built within QuPath30. We trained the FPN model using 3924 image tiles originating from 205 cases from the training dataset  with a ResNet-18 encoder for semantic segmentation of viable tumor areas using segmentation models . The batch size was 32 and the dataset was split into training and validation sets (80/20), resulting in 800,000 files for training and 200,000 files for validation. Data augmentation techniques such as random horizontal and vertical flipping and rotation were applied to the training data. Moreover, we used a dedicated color augmentation strategy by applying H&E stain normalization. We applied a non-linear activation function (sigmoid activation function) to the output of the final dense layer of the ResNet-18 given the binary nature of the classification task. Adam was used to update the model’s parameters as optimizer and a cross entropy was used as loss function. The learning rate was scheduled to decrease over time using an initial learning rate of 0.01, decay steps of 10,000 and a decay rate of 0.9. The model’s performance on the validation set was monitored using accuracy and the training process was stopped early if the validation accuracy would not improve for eight consecutive epochs. The total number of training steps in each epoch was 25000.35.To choose an architecture of a deep-convolutional neural network that would yield the best results, we randomly selected 500 cases from the whole cohort and evaluated the performance on 216 independent cases , followed by stain normalizationn = 884). Cases from the TCGA database were scanned at 20X magnification using Aperio slidescanners .Slides from Cologne, Giessen, Heidelberg and Maastricht were scanned using a NanoZoomer S360 Digital slide scanner with a pixel size of 0.23 μm/pixel (s2) are explained schematically in Supplementary Figs. The tile class prevalence (TP) and the variance of the probability of the HPV-positive class  for HPV-positive (Hpos); Eq. :2\documeCombined score; Eq. :3\documeTo evaluate the performance of the algorithm to determine HPV-status, we used either dichotomous HPV-status (p16/HPV-DNA) - where available - or either p16 or HPV-high risk DNA as ground truth. We have calculated the Youden index for the threshold of the classification of HPV-positive cases using the subset of validation cases as part of the training dataset to avoid overfitting our data. This has been calculated separately for the screening of architectures (methods) and the final ResNet-18 model. For the three-tier threshold of the combined score we applied the same criteria .p-value of less than 0.05 was considered statistically significant. All tests were two-sided. Statistical analysis was done with R and Python. All computation was performed using dual NVIDIA RTX 3090 GPUs.Univariate and multivariate analysis were conducted using a Cox proportional hazards model. Likelihood-ratio tests were performed as part of a Cox proportional hazards model . A Further information on research design is available in the Supplementary informationReporting Summary


The paper deals with the evaluation of the performance of an existing and previously validated CT based radiomic signature, developed in oropharyngeal cancer to predict human papillomavirus (HPV) status, in the context of anal cancer. For the validation in anal cancer, a dataset of 59 patients coming from two different centers was collected. The primary endpoint was HPV status according to p16 immunohistochemistry. Predefined statistical tests were performed to evaluate the performance of the model. The AUC obtained here in anal cancer is 0.68 [95% CI (0.32–1.00)] with F1 score of 0.78. This signature is TRIPOD level 4 (57%) with an RQS of 61%. This study provides proof of concept that this radiomic signature has the potential to identify a clinically relevant molecular phenotype  across multiple cancers and demonstrates potential for this radiomic signature as a CT imaging biomarker of p16 status. In particular, HPV + patients with oropharyngeal cancer present a markedly better prognosis and improved response to conventional radiotherapy3. Also, patients with anal cancer show a better prognosis and response to therapy when HPV + 4. Widely accepted methods for detection of HPV infection are in situ hybridization for viral DNA, HPV DNA or RNA PCR, and immunohistochemical investigation of the level of p16 expression, which strongly correlates with HPV infection5. However, these methods are time consuming and require biological patient samples. Image data analysis represents a novel non-invasive method of delivering reliable and quality results from standard-of-care medical images. The extraction of clinically relevant information from medical imaging is called radiomics. Radiomics is a rapidly emerging field, introduced in 2012, which concerns with the high-throughput mining of large amounts of quantitative features, derived from medical image such as CT/MRI/PET scans7. Radiomics is promising within decision support systems for precision medicine and its potential to predict p16 status in head and neck cancer has been recognized8. Previous studies have reported radiologic differences between p16 positive and negative cases in terms of qualitative radiologist’s readout of perfusion CT9. Furthermore, exploratory radiomic studies have shown that heterogeneity of image-based density is potentially associated with p16 status in oropharyngeal squamous cell carcinoma (OPSCC)10. Most of the studies investigating imaging phenotypes of tumors are based on single center data, which introduce bias to a model and limits its applicability. In particular, factors such as CT scanner, tube voltage, tube current, reconstruction kernel and contrast agent influence the results of quantitative analyses11. In this independent external validation study, we further investigate if a quantitative CT-based radiomic approach can objectively identify the p16 status of anal cancer in addition to OPSCC12, by validating a radiomic signature on patient data from two different institutions. With this study we aim to provide a proof of concept for radiomics to derive molecular information from standard medical images. Moreover, we demonstrate that the already developed and validated radiomics signature for head and neck cancer can also be useful in identification of HPV status of anal cancer patients.Human papillomavirus (HPV) is a common virus that can lead to certain types of cancer later in life. Several studies have shown that HPV status of cancer patients plays an important role in treatment outcomesTwo independent cohorts, for a total of 59 anal cancer patients treated with curative intent by surgery and/or radiation therapy with/without concurrent chemotherapy, were collected from University Hospital of Liège (CHU) (n = 18) and St James's Hospital (TCD). (n = 41) The patients cohort is composed of 12% of stage I, 40% of stage II, 45 of stage III and 3 of stage IV anal cancer. The HPV status of the patients was inferred from p16 immunohistochemistry status (54 + and 5−). All patients underwent pre-treatment CT imaging, according to the standard of care of the treating institution. The gross primary tumor volume (GTV) was manually segmented for each patient by experienced radiologists. Institutional review board approval was obtained from the Ethics committees of the University Hospital of Liege, Trinity College, Cork University Hospital and St. Luke Hospital. The need for informed consent was waived from the same ethics committees since the data were anonymized and retrospectively collected. The present work as been conducted in accordance with the Declaration of Helsinki.13. The schematic representation in Fig. Radiomics is based on the hypothesis that quantitative analysis of medical image data via automatic or semi-automatic software can provide more and better information than that of a physicianThe radiomics workflow is divided in four mains steps. First the imaging data are collected, and eventually preprocessed, dividing them in different set : then the region of interest (ROI) is segmented and annotated manually or (semi) automatically. From this region of interest handcrafted radiomics features are extracted, and divided into Size, Shape, Texture and Intensity features. The radiomics features are then used to train the AI model and the performances are validated in the test set and additionally in an external validation set.14. Details for the development of the radiomics signature for HPV status in OPSCC are reported elsewhere12. Briefly, the signature was built using regularized logistic regression and showed an AUC of 0.763 [95% CI (0.687–0.839)] in development. The signature class predictions were made with a probability cut-off of 0.5.In the external validation study presented here, prior to analysis, all images were resampled to isotropic voxels of 2 mm, using linear interpolation. A total of 37 radiomics features were calculated from five groups: tumor intensity, shape, texture, Wavelet and Laplacian of Gaussian. All features were extracted using the RadiomiX® software . Feature descriptions and mathematical definitions can be found in the literatureThe signature performances have been evaluated in terms of Precision , Sensiti15, we calculated also Negative predictive value (NPV) and Positive predictive value (PPV). The signature was also evaluated according to the Transparent Reporting of a multivariable prediction model for Individual Prognosis or Diagnosis (TRIPOD)16 and the Radiomics Quality Score (RQS)14. Statistical analysis was performed in R .Assuming a 85% prevalence of HPV positive anal cancer patientsThe model performance on the validation data set of anal cancer patients (n = 59) presents an AUC of 0.681 [95% CI 0.328–1.000)]. The ROC plot and the confusion matrix for the validation set are shown in Fig. 8–1.000].The signature showed discriminative power also for anal cancer, predicting the probability of p16 + (HPV +), or better the “HPV-ness” of the tumor. Table The RQS of the original signature, developed in OPSSC, is 50%. The additional validation with an external dataset, brings the RQS of the signature to 61%. Additionally, the original signature for OPSSC was TRIPOD level 2a (56%) while the new proposed model is a TRIPOD level 4 (57%) signature (See Supplementary Information).17 and were performed without validation, or only using data from a single institution, for both model development and validation. This is a major problem for the reliability of prediction models based on radiomics signature7. Previously published studies report that HPV positive tumors are more homogenous in CT density19. The homogeneity in turn can represent one of the reasons why HPV + tumors have a better therapeutic outcome and prognosis20. We show that the signature which was previously developed and validated in head and neck cancer, also shows discrimination power for anal cancer patients. This suggests that it would be possible to cautiously generalize these findings on tumor radiomics features beyond OPSCC. Furthermore, this study provides an additional insight into p16 (HPV) imaging phenotype. We observed that the p 16 positive tumors are characterized by lower contrast uptake, lower minimum density, and higher changes in the intensity of adjacent voxels. It is worth noting that is not possible to distinguish between p16 + and p16- anal tumors by visual inspection of the CT scan alone, and it has been proven a difficult task also for oropharyngeal cancer21. The difference in prevalence of anal cancer is important to consider in order to assess the performance of the signature. The prevalence of HPV positive anal cancers is 85%15 and needs to be taken into account in the implementation of the signature as decision support tool for clinicians. The main aim of such signature applied to anal cancer would be the identification of HPV-negative tumors, which can be assessed using the specificity and the NPV , were made with a probability cut-off of 0.5, meaning that the costs for false-positives and false-negatives were considered equal. In clinical practice, false positive have a much higher cost in term of patient management and healthcare quality and should be minimized. To achieve a clinically acceptable level of accuracy, further development and validation would be needed, including HPV DNA testing. The radiomics HPV prediction model, while reliable, should not supersede the traditional clinical decision-making approach, based on universally accepted methodology. However, radiomics has the potential to serve as a time-efficient, complementary method for HPV screening, also, for non-oropharyngeal SCCs26. Radiomics approaches can be used to perform retrospective biomarker studies on HPV status where tissue samples are not available or in countries where HPV testing is not routinely performed. Furthermore, additional improvement in inferring tumor HPV status may be achieved when combining radiomics with clinical features27.Another open question is related to the rate of false positive in the immunohistochemical test for 16p. Part of the OPSCC patients that test positive for p16 immunohistochemistry are in fact HPV DNA negativeThe discriminating power of the radiomics signature for p16 status determination, developed for OPSCC, was also validated for anal cancer patients. These preliminary but encouraging results may pave the road for further generalization of CT image features of HPV related tumors. The use of a larger cohort with p16 and HPV DNA test data, as well as the inclusion of other possible cancer types which shown a correlation with HPV status would be instrumental in this regard.Supplementary Information.