The genomic landscape of cutaneous squamous cell carcinoma in Japan

Comprehensive studies of the genetic profiles of cutaneous squamous cell carcinoma (cSCC) in Japanese patients have been lacking, although an understanding of these profiles is crucial for improving treatment outcomes. Since 2019, comprehensive genomic profiling (CGP) has been covered by Japan's health insurance, and the resulting data have been compiled into a comprehensive database by the country's Center for Cancer Genomics and Advanced Therapeutics (C-CAT). In this retrospective study, we used CGP data from the C-CAT database to analyze genomic characteristics of cSCC in Japanese patients. The patients' clinical and genomic data, including the chemotherapy regimens, tumor mutational burden (TMB), and survival status, were obtained. We analyzed the cases of 152 patients, with only those evaluated by the FoundationOne® CDx included for accuracy. Among the 152 patients, the most common gene oncogenic alterations were observed in TP53 (67%), CDKN2A (54%), TERT (49%), CDKN2B (33%), and NOTCH1 (18%). TMB-high (≥10 mut/Mb) was observed in 27% (n = 41) of the patients, with a median age of 75 years for this group. TMB-low (<10 mut/Mb) was observed in 73% (n = 111) of the patients; their median age was 67 years.