Cancer immunotherapy restores and/or enhances effector function of CD8+ T cells in the tumor microenvironment1,2.,CD8+ T cells activated by cancer immunotherapy execute tumor clearance mainly by inducing cell death through perforin-granzyme- and Fas/Fas ligand-pathways3,4.,Ferroptosis is a form of cell death that differs from apoptosis and results from iron-dependent lipid peroxide accumulation5,6.,Although it was mechanistically illuminated in vitro7,8, emerging evidence has shown that ferroptosis may be implicated in a variety of pathological scenarios9,10.,However, the involvement of ferroptosis in T cell immunity and cancer immunotherapy is unknown.,Here, we find that immunotherapy-activated CD8+ T cells enhance ferroptosis-specific lipid peroxidation in tumor cells, and in turn, increased ferroptosis contributes to the anti-tumor efficacy of immunotherapy.,Mechanistically, interferon gamma (IFNγ) released from CD8+ T cells downregulates expression of SLC3A2 and SLC7A11, two subunits of glutamate-cystine antiporter system xc-, restrains tumor cell cystine uptake, and as a consequence, promotes tumor cell lipid peroxidation and ferroptosis.,In preclinical models, depletion of cyst(e)ine by cyst(e)inase in combination with checkpoint blockade synergistically enhances T cell-mediated anti-tumor immunity and induces tumor cell ferroptosis.,Expression of system xc- is negatively associated with CD8+ T cell signature, IFNγ expression, and cancer patient outcome.,Transcriptome analyses before and during nivolumab therapy reveal that clinical benefits correlate with reduced expression of SLC3A2 and increased IFNγ and CD8.,Thus, T cell-promoted tumor ferroptosis is a novel anti-tumor mechanism.,Targeting tumor ferroptosis pathway constitutes a therapeutic approach in combination with checkpoint blockade.
Women diagnosed with cutaneous melanoma have a survival advantage compared to men, which has been hypothesized to be due to difference in behavior and/or biology (sex hormones).,It remains controversial whether this advantage is dependent on age or stage of disease.,We sought to compare melanoma‐specific survival between females in pre, peri, and postmenopausal age groups to males in the same age group, adjusting for stage of disease.,This is a retrospective population‐based cohort study using the Surveillance, Epidemiology, and End Results (SEER) database.,Patients diagnosed from 1 January 1992 through 31 January 2011 with primary invasive cutaneous melanoma were included in our cohort.,Melanoma‐specific survival was the main outcome studied.,Of the 106,511 subjects that were included, 45% were female.,Females in all age groups (18-45, 46-54, and ≥55) with localized and regional disease, were less likely to die from melanoma compared to males in the same age group.,Among patients with localized and regional disease, the relative risk of death due to melanoma increased with advancing age at diagnosis; this increase was more pronounced among females than males.,In contrast, we observed no female survival advantage among patients with distant disease and no effect of age on relative risk of death from melanoma.,Females with localized and regional melanoma have a decreased risk of death compared to males within all age groups.,Our data show no differences in survival between men and women with metastatic melanoma, indicating that the influence of sex on survival is limited to early stage disease but not confined to pre or perimenopausal age groups.