A genetic variant in microRNA target site of TGF-β signaling pathway increases the risk of colorectal cancer in a Chinese population

Evidence shows that single-nucleotide polymorphisms in microRNA (miRNA) target sites can create, destroy, or modify the miRNA/mRNA binding, therefore modulating gene expression and affecting cancer susceptibility. The transforming growth factor-beta (TGF-beta) signaling pathway plays a pivotal role in tumor initiation and progression. Intriguingly, recent advances of genome-wide association studies have identified multiple risk loci in this pathway to be associated with risk of colorectal cancer (CRC). To test the hypothesis that genetic variants in miRNA target sites in genes of the TGF-beta signaling pathway may also be associated with CRC risk, we first systematically scanned the single-nucleotide polymorphisms (SNPs) in genes of TGF-beta signaling pathway which potentially affect the miRNA/mRNA bindings. Through a series of filters, we narrowed down these candidates to four SNPs. Then, we conducted a case-control study with 600 CRC patients and 638 controls in Han Chinese population. We observed that compared with A carriers (AA + AG), the GG genotype of rs12997:ACVR1 is associated with a significantly higher risk of CRC (OR = 1.52, 95 % confidence interval (95 % CI) = 1.04-2.21, P = 0.031), particularly in nonsmokers with a higher OR of 1.63 (95 % CI = 1.04-2.55, P = 0.032). Our study suggested that SNPs in miRNA target sites could contribute to the likelihood of CRC susceptibility and emphasized the important role of polymorphisms at miRNA-regulatory elements in carcinogenesis.