Genetic variation in the miR-4273-5p target site is associated with a risk of colorectal cancer.

PURPOSE

MicroRNAs (miRNAs) are noncoding RNAs that play roles as tumor suppressors or oncogenes by regulating the expression of target genes via binding to seed-match sequences. Polymorphisms in the miRNA-binding site of a target gene can alter miRNA binding and potentially affect the risk of cancer. The objective of this study was to identify single-nucleotide polymorphisms (SNPs) in miRNA-binding sites and assess their involvement in the risk of colorectal cancer (CRC).

MATERIALS AND METHODS

SNPs in the 3' untranslated regions of genes were selected and assessed for their effects on CRC risk in Korean population using participants in Korean Cancer Prevention Study-II. A detailed study was carried out with the SNP in the 3' untranslated region of the translocase of outer mitochondrial membrane 20 () gene. A case-control study (1,545 controls and 620 CRC cases) was conducted to analyze the relationship between polymorphism at and the risk of CRC. An interacting miRNA was predicted using web-based software programs, and its interaction with in CRC cell lines was investigated by using a luciferase assay.

RESULTS

Individuals carrying the AG genotype (G allele) had a 1.721-fold increased risk for CRC in comparison with those with the AA genotype (A allele). The miRNA miR-4273-5p was found to specifically interact with the A allele of and to suppress the expression of the target gene () in CRC cell lines.

CONCLUSION

is an independent genetic risk factor for CRC susceptibility. Our study suggests a mechanism of how this SNP contributes to CRC carcinogenesis.