PI3KCA mutation as an independent pronostic factor in anal squamous cell carcinoma treated by abdomino-perineal resection: Evidence from a retrospective cohort of 148 patients.

e15060Background: A better understanding of the molecular profile of the anal squamous cell carcinomas (ASCCs) is necessary to consider new therapeutic approaches, and the identification of prognostic and predictive factors for response to treatment. Methods: We retrospectively analyzed tumors from ASCC patients for mutational analysis of KRAS, NRAS, HRAS, BRAF, PI3KCA, MET, TP53 and FBXW7 genes. Results: Specimen from 148 patients were analyzed: 96 treatment-naive tumors and 52 recurrences after initial radiotherapy (RT) or chemoradiotherapy (CRT). Mutations of KRAS, PIK3CA, FBXW7 and TP53 genes was present respectively in 3 (2.0%), 30 (20.3%), 9 (6.1%) and 7 tumors (4.7%). The distribution of the mutations was similar between treatment-naive and relapse tumors, except for TP53 mutations being more frequent in recurrences (p= 0.0005). In patients treated with abdomino-perineal resection (APR) after relapse (n = 38, median follow up of 218 months), overall survival was significantly correlated with HPV16 ...