Objective     To explore the relationship between polymorphism of Serpin B1 (serine protease inhibitor

clade B

member 1) gene at H67Q site and Serpin B1 level in the peripheral blood of patients with gastric cancer. Methods     A total of 350 cases diagnosed with gastric cancer in our hospital from Jan 2013 to Dec 2015 were recruited as case group

and 350 cases of matched healthy people as control group. PCR amplification-combined DNA direct sequencing was applied to test Serpin B1 gene polymorphism at the site of H67Q in both groups using genomic DNA isolated from peripheral blood. The level of Serpin B1 protein in peripheral blood was detected with ELISA and compared among different genotype subgroups. Logistic regression analysis was assessed the relationship between H67Q site polymorphism of Serpin B1 gene and gastric cancer. Results      Allelic genes T and G were identified at H67Q site of Serpin B1 gene

resulting in 3 genotypes of wild-type homozygous (TT)

heterozygous mutant (GT)

and homozygous mutant (GG). The frequencies of GG and GT genotypes

and allelic gene G in case group were significantly higher than those in control group (P0.05). Serpin B1 protein level was higher in case versus control group (P0.05). Among the 3 genotype groups

GG group had the highest level of Serpin B1 followed by GT group

and TT group had the lowest level. The difference between each group comparison was statistically significant（P0.05）. Results of logistic regression analysis showed that GG genotype (OR=9.485，95%CI: 2.169~44.283

P=0.006) and allelic gene G (OR=5.105，95%CI: 1.847~13.360，P=0.014) were independent risk factors for colorectal cancer. Conclusion     Polymorphism of Serpin B1 gene at H67Q site is related to gastric cancer.