Background: Gastric cancer is one of the four most common cancer that causing death worldwide. Genome-Wide Association Studies (GWAS) have shown that genetic diversities MUC1 (Mucin 1) and PSCA (Prostate Stem Cell Antigen) genes are involved in gastric cancer. The aim of this study was avaluating the association of rs4072037G > A polymorphism in MUC1 and rs2294008 C > T in PSCA gene with risk of gastric cancer in northern Iran. Methods: DNA was extracted from 99 formalin fixed paraffin-embedded (FFPE) tissue samples of gastric cancer and 96 peripheral blood samples from healthy individuals (sex matched) as controls. Two desired polymorphisms, 5640G > A and 5057C > T for MUC1 and PSCA genes were genotyped using PCR-RFLP method. Results: The G allele at rs4072037 of MUC1 gene was associated with a significant decreased gastric cancer risk (OR = 0.507, 95% CI: 0.322–0.799, p = 0.003). A significant decreased risk of gastric cancer was observed in people with either AG vs. AA, AG + AA vs. GG and AA+GG vs. AG genotypes of MUC1 polymorphism (OR = 4.296, 95% CI: 1.190–15.517, p=0.026), (OR = 3.726, 95% CI: 2.033–6.830, p = 0.0001) and (OR = 0.223, 95% CI: 0.120–0.413, p = 0.0001) respectively. Finally, there was no significant association between the PSCA 5057C > T polymorphism and risk of gastric cancer in all genetic models. Conclusion: Results indicated that the MUC1 5640G > A polymorphism may have protective effect for gastric cancer in the Northern Iran population and could be considered as a potential molecular marker in gastric cancer.
