A potentially functional polymorphism in the promoter region of miR-34b/c is associated with an increased risk for primary hepatocellular carcinoma.

The miR-34 family members are direct transcriptional targets of tumor suppressor p53, and loss of miR-34 function can impair p53-mediated cell cycle arrest and apoptosis. A potentially functional SNP rs4938723 (T > C) was found in the promoter region of pri-miR-34b/c (423 bp from the transcription start site), located in the CpG island and might affect transcription factor GATA binding and therefore pri-miR-34b/c expression. In our study, we hypothesized that SNPs miR-34b/c rs4938723 and TP53 Arg72Pro may independently or jointly contribute to primary hepatocellular carcinoma (HCC) susceptibility. We then genotyped the 2 SNPs in a case-control study of 501 patients with primary HCC and 548 cancer-free controls in a Chinese population. We observed that the variant genotypes of miR-34b/c rs4938723 were associated with significantly increased HCC risks compared with the wild-type TT genotype (adjusted OR = 1.37, 95% CI =1.06-1.78 for TC; OR = 1.53, 95% CI = 1.02-2.31 for CC and OR = 1.40, 95% CI = 1.10-1.80 for TC/CC). Furthermore, we found a significant interaction between alcohol drinking and SNP rs4938723 on HCC risk (p = 0.05 for multiplicative and p = 0.01 for additive interaction). However, we did not find any main effect of TP53 Arg72Pro on HCC risk in this population. These findings indicate that the potentially functional SNP rs4938723 in the promoter region of pri-miR-34b/c may contribute to the susceptibility of HCC in this Chinese population.