Primary Cutaneous Melanoma Microbiome Is Associated with Overall Survival and Recurrence

Melanoma contributes to the highest deaths from skin cancer. The primary melanoma intratumoral microbiome association with clinical outcomes has not been described. We hypothesized that specific microbes may be associated with clinical outcomes as found in other cancers. We performed 16S V1-V3 ribosomal RNA gene-based microbial profiling of primary melanoma formalin-fixed paraffin-embedded specimens and found that the bacterial composition of cutaneous melanoma (β-diversity analysis) was associated with both overall survival and recurrence (P = .024 and P = .025), and a higher effective number of species (α-diversity) was associated with both worse overall survival (P = .048; hazard ratio = 2.13, 95% confidence interval = 1.15-6.02) and earlier time to recurrence (P = .016; hazard ratio = 2.13, 95% confidence interval = 1.15-3.94). Cutibacterium granulosum was associated with better overall survival and lower recurrence. Lower recurrence was also associated with C acnes, Corynebacterium kefirresidentii, and an unclassified Corynebacterium. Conversely, both higher recurrence and worse overall survival were associated with Leuconostoc inhae, Streptococcus salivarius, Collinsella sp900764415, and an unclassified Porphyromonas. Although the bacterial microbiome for nasal and oral melanomas was not associated with clinical outcomes, 5 bacterial operational taxonomic units were significantly associated with recurrence versus no recurrence by supervised β-diversity analysis (P = .023). These findings highlight a potential role of microbes in the pathophysiology of melanoma.