Polymorphisms in microRNA genes as predictors of clinical outcomes in colorectal cancer patients

Abstract

Colorectal cancer (CRC) is one of the most frequently diagnosed malignancies worldwide. It is routinely cured by a 5-fluorouracil (5-FU)-based chemotherapy which improves outcomes in patients. We investigated the effect of single nucleotide polymorphisms (SNPs) in two microRNA (miRNA)-encoding genes that have been previously reported as important in prognosis in patients with stage III CRC and treated with 5-FU-based chemotherapy. Two SNPs (rs4919510 in miR-608 and rs213210 in miR-219-1) were genotyped in 1083 CRC patients recruited in the Czech Republic to evaluate their effect on clinical outcomes. Carriers of the variant T allele in rs213210 and receiving 5-FU chemotherapy were associated with a significantly worse survival [hazard ratio (HR) = 2.18; 95% confidence interval (CI): 1.20-3.98; adjusted P = 0.01] and an increased risk of relapse (HR = 1.94; 95% CI: 1.16-3.25; adjusted P = 0.01). After further stratification for tumor grading, stage III patients carrying the G allele of rs4919510 and undergoing adjuvant chemotherapy were at decreased risk of relapse (HR = 0.44; 95% CI: 0.20-0.94; adjusted P = 0.03). The present study confirms that variations in miRNA-encoding genes may be an important factor for modulating CRC prognosis and predicting therapy response.