Expression of nucleotide excision repair protein ERCC1 in tumor tissue as a prognostic factor in colorectal cancer

At present, biomarkers of tumor resistance to platinum drugs in colorectal cancer are of much concern. Relapses and metastases occur in 35 % of patients with colorectal cancer (stages I-III) after adjuvant polychemotherapy with platinum-based anticancer drugs within the first 5 years. Resistance to platinum-based drugs is determined by a number of factors, including increased DNA repair capacity. The aim of the study is to evaluate the prognostic role of ERCC1 expression in tumor tissue in colorectal cancer. Materials and Methods. The authors studied the expression of the nucleotide excision repair protein ERCC1 in tumor tissue as a prognostic marker for adjuvant chemotherapy FOLFOX/XELOX in patients with colorectal cancer (stages II-IV). The correlation between ERCC1 expression in tumor tissue and chemotherapy effectiveness, clinical stage, age, survival, differentiation, and EGFR pathway mutations (NRAS, KRAS, BRAF) was assessed. Results. ERCC1 expression was detected in 46.9 % of tumor tissue samples and in 88.9 % of resection line tissue samples. In patients with ERCC1 overexpression, the median survival was significantly lower than in patients with low ERCC1 expression. In tumors with NRAS and BRAF mutations, no ERCC1 expression was observed. No differences were determined in patient according to the disease stage, tumor differentiation, and mutations. Cancer tumors is an independent predictor of FOLFOX/XEL OX chemotherapy resistance.