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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. [ABSTRACT FROM AUTHOR]

Integrons play an important role in multidrug resistance. The integron platform codes for integrase (intI) that is required for gene cassette integration through site-specific recombination. The recombination crossover occurs between the G and TT nucleotides in non-palindromic attI and palindromic attC sites. The aim of this study was to establish an efficient in vitro assay for integrase purification and activity detection. To this end, the intI gene was cloned into the pET-22b plasmid. Then, the resulting recombinant plasmid was transformed into Escherichia coli Origami™ strain. The recombinant protein expression was confirmed by sodium dodecyl sulphate-polyacrylamide gel electrophoresis (SDS-PAGE) and western blot assays. The recombinant intI protein was purified by nickel–nitrilotriacetic acid (Ni–NTA) affinity chromatography, and its activity was measured by a newly introduced assay. Briefly, specific primers for each side of attI and attC were used, thereby, a polymerase chain reaction would be performed, if a fused plasmid containing both attI and attC sites was created upon recombination. SDS-PAGE and western blotting confirmed the presence of a 38-kDa recombinant protein. Optimum conditions were established for the measurement of the integrase activity and a new model assay was conducted to analyse the recombination activity in vitro. Although the electrophoretic mobility shift assay is an efficient and reliable method, the newly introduced assay provided new or enhanced capability to determine the integrase activity, suggesting that there is no need for expensive and advanced equipment. [ABSTRACT FROM AUTHOR]