Targeted panel sequencing of pharmacogenes and oncodrivers in colorectal cancer patients reveals genes with prognostic significance

Abstract Background Colorectal cancer is still the second leading cause of cancer-related deaths and thus biomarkers allowing prediction of the resistance of patients to therapy and estimating their prognosis are needed. We designed a panel of 558 genes with pharmacogenomics records related to 5-fluorouracil resistance, genes important for sensitivity to other frequently used drugs, major oncodrivers, and actionable genes. We performed a target enrichment sequencing of DNA from tumors and matched blood samples of patients, and compared the results with patient prognosis stratified by systemic adjuvant chemotherapy. Results The median number of detected variants per tumor sample was 18.5 with 4 classified as having a high predicted functional effect and 14.5 moderate effect. APC, TP53 , and KRAS were the most frequent mutated genes (64%, 59%, and 42% of mutated samples, respectively) followed by FAT4 (23%), FBXW7 , and PIK3CA (16% for both). Patients with advanced stage III had more frequently APC , TP53 , or KRAS mutations than those in stages I or II. KRAS mutation counts followed an increasing trend with grade (G1 5% frequency and positive Manhattan plot based on 3-year RFS, rs72753407 in NFACS , rs34621071 in ERBB4 , and rs2444274 in RIF1 were significantly associated with RFS, OS or both. Conclusions The present study identified several putative somatic and germline genetic events with prognostic potential for colorectal cancer that should undergo functional characterization.