Immunotherapy prolongs survival in only a subset of melanoma patients, highlighting the need to better understand the driver tumor microenvironment.,We conducted bioinformatic analyses of 703 transcriptomes to probe the immune landscape of primary cutaneous melanomas in a population-ascertained cohort.,We identified and validated 6 immunologically distinct subgroups, with the largest having the lowest immune scores and the poorest survival.,This poor-prognosis subgroup exhibited expression profiles consistent with β-catenin-mediated failure to recruit CD141+ DCs.,A second subgroup displayed an equally bad prognosis when histopathological factors were adjusted for, while 4 others maintained comparable survival profiles.,The 6 subgroups were replicated in The Cancer Genome Atlas (TCGA) melanomas, where β-catenin signaling was also associated with low immune scores predominantly related to hypomethylation.,The survival benefit of high immune scores was strongest in patients with double-WT tumors for BRAF and NRAS, less strong in BRAF-V600 mutants, and absent in NRAS (codons 12, 13, 61) mutants.,In summary, we report evidence for a β-catenin-mediated immune evasion in 42% of melanoma primaries overall and in 73% of those with the worst outcome.,We further report evidence for an interaction between oncogenic mutations and host response to melanoma, suggesting that patient stratification will improve immunotherapeutic outcomes.
Established prognostic factors are of limited value to predict long-term survival and benefit from metastasectomy in advanced melanoma.,This study aimed to identify prognostic factors in patients with distant metastasis.,We analysed overall survival of 855 institutional melanoma patients with distant metastasis by bivariate Kaplan-Meier survival probabilities and multivariate Cox hazard regression analysis.,Serum lactate dehydrogenases (LDH), S100B, the interval between initial diagnosis and occurrence of distant metastasis, the site of distant metastases, and the number of involved distant sites were significant independent prognostic factors in both bivariate and multivariate analyses.,Visceral metastases other than lung (hazard ratio (HR) 1.8), elevated S100B (HR 1.7) and elevated LDH (HR 1.6) had the highest negative impact on survival.,Complete metastasectomy was likewise an independent prognostic factor in multivariate analysis.,This treatment was associated with favourable survival for patients with normal LDH and S100B values (5-year survival, 37.2%).,The serum markers LDH and S100B were both found to be prognostic factors in melanoma patients with distant metastasis.,Furthermore, complete metastasectomy had an independent favourable prognostic impact in particular for the patient subgroup with normal LDH and S100B values.