Genetic Association Study of a Pri-miR-34b/c Polymorphism with Gastric Cancer

Recently studies have demonstrated that miR-34b/c are abnormally expressed in gastric cancer. A single nucleotide polymorphism (SNP) rs4938723 (T>C) has been found in the promoter region of Pri-miR-34b/c which is in the CpG island and may affect miR-34b/c expression by both genetic and epigenetic mechanisms. The T to C shift of the rs4938723 polymorphism was predicted to influence the GATA-X transcription factor bindingand thus the expression of many target genes related to tumor differentiation and carcinogenesis. The purpose of the present case-control study was to investigate the association between the miR-34b/c rs4938723 polymorphisms and the risk of gastric cancer. We analyzed the distribution of the pri-miR-34b/c polymorphism in 68 patients with gastric cancer and 62 age-, gender-, ethnicity-, and living area-matched controls using allele-specific tetra-primer PCR. Results of the study demonstrated that out of 68 for the patients, 22 were TT, 46 were TC. The frequencies of genotype TT and TC for patients were 32 and 68 % respectively. The frequencies of allele T and C in patients were 0.66 and 0.34 respectively. While for the control group, 18 subjects were of TT, 44 were TC. In control group the genotype frequencies for the TT and TC were 29 and 71 % respectively. The frequency of the allele T was 0.65 and allele C was 0.35. No statistically significant differences were found in the allele or genotype distributions of the miR-34b/c rs4938723 polymorphism among gastric cancer patients and cancer-free control subjects (P = 0.82). In conclusion, the miR-34b/c polymorphism seems not to be a potential risk factor for developing of gastric cancer among Iranian patients. Keywords: miR-34b/c, rs4938723, Polymorphism, Gastric cancer