Pri-miR-34b/c rs4938723 polymorphism is associated with a decreased risk of gastric cancer

Previous studies have demonstrated that miR-34 family members are abnormally expressed in gastric cancer. Overexpression of the miR-34 family suppresses gastric carcinogenesis, whereas downregulation of the miR-34 family promotes tumorigenesis. p53 can bind to the promoter region of miR-34b/c, leading to an increase of miR-34b/c expression. Recently, a variant in the promoter region of pri-miR-34b/c (rs4938723) has been discovered, with the function of altering the binding efficiency of transcription factor GATA. The purpose of this study was to examine the role of the miR-34b/c rs4938723 and TP53 Arg72Pro polymorphisms in the susceptibility of gastric cancer. We analyzed the distribution of the two polymorphisms in 197 patients with gastric cancer and 289 age-, gender-, ethnicity-, and living area-matched controls using polymerase chain reaction-restriction fragment length polymorphism and DNA direct sequencing. We found that the CT and CT/CC genotypes of the miR-34b/c rs4938723 were associated with a significantly decreased risk of gastric cancer compared with the TT genotype (CT vs. TT: odds ratio [OR]=0.66; 95% confidence interval [95% CI], 0.45-0.97; and CT/CC vs. TT: OR=0.67; 95% CI, 0.47-0.97, respectively). Combined analysis showed that subjects carrying the miR-34b/c rs4938723 CT/CC and TP53 CG/CC genotypes had a 0.62-fold decreased risk to develop gastric cancer compared with subjects carrying the miR-34b/c rs4938723 TT and TP53 CG/CC genotypes (OR=0.62; 95% CI, 0.40-0.96). These findings suggest that the miR-34b/c rs4938723 may individually and jointly have a protective effect on the risk of gastric risk.