A functional variant rs353292 in the flanking region of miR-143/145 contributes to the risk of colorectal cancer.

MicroRNA (miR)-143 and miR-145 have been identified as molecular regulators in cell proliferation, cell growth, clone formation, apoptosis, cell cycle, invasion, and migration. We previously found that rs353292 in the flanking region of miR-143/145 showed a high frequency in patients with colorectal cancer (CRC). To identify whether the rs353292 polymorphism is a risk factor for CRC, we conducted this study with larger samples. A total of 809 patients with CRC and 1005 gender matched controls were collected. The rs353292 polymorphism was genotyped by using TaqMan allelic discrimination. Dual luciferase reporter assay was carried out to measure the transcriptional activity. We found that the rs353292 polymorphism was associated with an increased risk for developing CRC in heterozygous comparison (adjusted OR = 1.70, 95% CI, 1.32-2.20, P < 0.001), dominant genetic model (adjusted OR = 1.62, 95% CI, 1.26-2.09, P < 0.001), and allele comparison (adjusted OR = 1.46, 95% CI, 1.16-1.84, P = 0.001). The rs353292 CT/TT carriers exhibited a lower expression of miR-143 compared to the CC carriers (P = 0.04). Moreover, the pGL3-rs353292T displayed a significantly lower luciferase activity than pGL3-rs353292C (P < 0.01). These findings indicate that the rs353292 polymorphism is functional and may be a risk factor for the development of CRC.