The Influence Of SMAD7 Gene On Risk Of Gastric Cancer Based On SNP

Gastric cancer is the 2nd most common malignant tumor in the world, the distribution of gastric cancer cases shows obvious regional divergence and gender differences: North America, Europe and Africa with the low incidence, a high incidence of gastric cancer is in Asia and its incidence and mortality of male to female ratio is about 2:1. Pathogenesis of gastric cancer has not been fully elucidated, but a lot of etiology studies have shown that the development of colorectal cancer is a multi-stage, multi-step, multi-gene involved process, and the genetic factor result in the susceptibility of gastric cancer.SMAD7 is an inhibitory SMAD and a negative regulator of the transforming growth factor β (TGF-β) signaling pathway, which plays important roles in tumor initiation, invasion and metastasis. Currently, much attention has been drawn to those SNPs associated with gastric cancer within SMAD7 gene. But the results of SNPs associated with gastric cancer studies led to contradictory conclusions about the effect of the SNPs on susceptibility to gastric cancer.Thus, to analyze whether those SNPs located in SMAD7 gene are correlated with gastric cancer in Chinese Han as that in western populations, we performed this association analysis with 5 SNPs in SMAD7 gene in Yunnan Han nationality.In this study, a total of 250 gastric cancer cases and 240 cancer-free control were recruited from the First People’s Hospital of Yunnan Province. All individuals are of Han nationality in Yunnan. Genotyping for five tagging SNPs of SMAD7 gene was performed by polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP). The association between the genetic variation (allele, genotype and haplotype) and gastric cancer was examined by logistic regression.The results show that SNPs of rs11874392 and rs1316447 were detected association with gastric cancer, especially the latter one. A significant difference of distribution in both genotype and allele for rs1316447 were observed between case and control, the mutation (or minor) allele T was associated with an increased risk to gastric cancer. And the results also indicated that there were some differences in the effect of SMAD7 SNPs by stratified with male gender.