Correlations between microsatellite instability, ERCC1/XRCC1 polymorphism and clinical characteristics, and FOLFOX adjuvant chemotherapy effect of colorectal cancer patients

•MSI was significantly correlated with histopathological differentiation and CRC family history.•MSI may influence the outcome of colorectal cancer patients treated with mFOLFOX6 adjuvant chemotherapy.•These biomarkers may be diagnostic and be used to predict the prognosis and effect of chemotherapy. Patients with MSI colorectal tumor have good prognosis and cannot benefit from 5-fluorouracil (5-Fu)-based chemotherapy reported by previous studies. While, single nucleotide polymorphisms (SNP) of ERCC1 and XRCC1 have be proved to influence clinical outcome of colorectal cancer patients treated with oxaliplatin-based chemotherapy. We aim to study the correlation between molecular status and clinical- pathological features, and their effect on CRC patients' clinical outcome treated with mFOLFOX6 adjuvant chemotherapy. In this study, MSI status was determined in tumors and paired normal tissues from 101 colorectal cancer (CRC) patients. We also examined SNP of ERCC1 (c. C354T) and XRCC1 (c.G1196A) in 83 and 85 patients' blood. MSI was found to be significantly correlated with well/moderate histopathological differentiation (p = 0.038) and CRC family history (p = 0.003). CEA and CA19-9 levels was positive correlated significantly by Spearman correlation analysis (Pearson's r = 0.823, p