Abstract
MicroRNAs (miRNAs), endogenous small noncoding RNAs (ncRNAs), play crucial roles in cancer development. Many studies have demonstrated that miRNAs can serve as diagnostic and therapeutic biomarkers for malignancies. Additionally, single nucleotide polymorphisms (SNPs) located in miRNA functional regions have been reported to be involved in cancer susceptibility. In this study, we investigated the associations between SNPs located in miRNA functional regions and colorectal cancer (CRC) susceptibility. We systematically screened all candidate miRNAs and their SNPs and then evaluated the relationships between the SNPs and CRC susceptibility in a Han Chinese population including 878 patients with CRC and 884 controls. Genotyping was performed by TaqMan assay. After comprehensively screening the miRNAs and SNPs, we elected to evaluate the association between SNP rs2682818 in miR-618 and CRC susceptibility. We found that the AA and AC/AA genotypes of rs2682818 were associated with a decreased risk of CRC compared with the CC genotype (odds ratio (OR) = 0.54, 95% confidence interval (CI) = 0.37-0.79 for AA vs. CC in codominant model; OR = 0.82, 95% CI = 0.68-0.99 for AC/AA vs. CC in dominant model). However, we obtained no statically significant results in our subgroup analyses. SNP rs2682818 in miR-618 has potential as a biomarker for individuals with high CRC susceptibility. Our findings need to be verified in studies including larger samples. Moreover, molecular functional studies of miR-681 must be performed to confirm its relationship with CRC.