307 Functional analysis of the genomic abnormalities of non uv-induced cutaneous squamous cell carcinomas

Skin squamous cell carcinoma (SCC) is the second most common skin cancer and mainly caused by cumulative UV exposure. However, SCC also arises independently of exposure, on sites sustained damage like chronic ulcers, scars, inflammatory diseases Hidradenitis suppurativa. Here we aimed to decipher genomic abnormalities, non-UV cutaneous SCC. We collected FFPE samples from a cohort 31 SCCs patients, including five HS, four leg ulcers eight DREB. DNA was extracted sequenced using illumina TSO500 panel 525 genes. Tumor Mutational burden at least 6 times lower than induced The predominant mutational signature clock-wise signature. By comparing frequency driver mutations, found TP53, NOTCH1 were significantly less frequently mutated Interestingly, KMT2B (a histone methyl transferase) in 11/31 this proportion higher These mutations high impact loss-of-function suggesting potential Suppressor Gene function. then performed vitro MTT proliferation wound healing/migration assays SCC-13 A-431 lines after knock down siRNA. that knocking expression does not affect migration, however, it increases migration. Altogether, our results identify as TSG are currently performing vivo experiments further its role progression.