Abstract:

Objective To investigate the correlation between colorectal cancer (CRC) and the single nucleotide polymorphism (SNP) in miR-146a C→G (rs2910164), as well as the expression level of miR-146a. Methods Colorectal cancer and adjacent normal tissues in 106 CRC patients (the CRC group) and normal tissues in 53 healthy controls (the control group) were obtained. Alleles of SNP were determined with gene sequencing method and the correlation between different genotypes and the occurrence and metastasis of CRC was analyzed. Patients with or without metastasis were assigned to the T1 group or the T0 group. Real-time-PCR was used to measure and compare miR-146a expressions in colon tissues with different genotypes. miR-146a expressions in cancer and adjacent normal tissues were compared and miR-146a expressions in cancer tissues were compared between the T1 group and the T0 group. Results The distribution of miR-146a genotypes in the CRC group was different from that in the control group. The Logistic regression analysis showed that GG and GC genotypes were risk factors for CRC. The controls carrying GG and GC genotypes had lower miR-146a expressions in colon tissues as compared with those carrying CC genotype. Cancer tissues in CRC patients had lower miR-146a expressions as compared with adjacent normal tissues. The distribution of genotypes in the T1 group was also different from that in the T0 group. The T1 group had a higher proportion of GG genotype. The Logistic regression analysis showed that GG genotype was a risk factor for CRC metastasis. Patients in the T1 group had lower miR-146a expressions in cancer tissues. GG genotype carriers had higher expression levels of EGFR and IRAK-1. Conclusion The G allele in the SNP of miR-146a is a risk factor for the incidence and metastasis of CRC. The mechanism may be related to lower miR-146a expression caused by the SNP and resulting higher expressions of EGFR and IRAK-1.

Key words: miR-146a, colorectal cancer, single nucleotide polymorphism