MicroRNAs (miRNAs) are small noncoding RNAs with regulatory functions as tumor suppressors and oncogenes. The rs2910164 is a C to G polymorphism located within the sequence of miR-164a precursor, which leads to a change from a C:U pair to a G:U mismatch in its stem region. Recent evidence suggested that the rs2910164 SNP in miR-146a was associated with development of familial breast and ovarian cancers, and prostatic cancer. The aim of this study was to investigate the association between this genetic variant and prognosis of colorectal cancer (CRC) operated curatively.Methods
A total of 343 CRC patients who underwent curative surgery were consecutively enrolled between 2004 and 2006. DNA was extracted from fresh frozen normal tissue and miR-146 polymorphism was genotyped by polymerase chain reaction–restriction fragment length polymorphism (PCR-RFLP).Results
With a median follow-up of 42.3 months, the combined GG + CG genotype demonstrated a better survival outcome compared with the CC genotype in Kaplan–Meier survival analysis. Multivariate analysis showed that the G allele of miR-146 was associated with better progression-free and disease-specific survival as a dominant model adjusted to age, sex, histologic grade and stage [HR = 0.54 and 0.49; P = 0.018 and 0.025, respectively]. Moreover, the tumors containing the G allele were histologically associated with more prominent lymphovascular invasion.Conclusions
Our results suggest that miR-146 polymorphism is a possible prognostic marker in operated CRC patients in Korean.