Purpose To detect the expression of Snai2 mRNA in gastric carcinoma and normal gastric mucosa and analyze its significance.Methods Total RNA was extracted with TRIzol from 30 cases of gastric carcinoma and mRNA was transcribed reversely into cDNA.The expression of Snai2 mRNA was examined by real-time PCR; then mRNA probes were prepared, the expression of Snai2 mRNA was detected by in situ hybridization on a tissue array,including normal gastric mucosa (20 cases) and gastric carcinoma (100 cases).Results Real-time PCR data showed they had different expression in different degrees of differentiation of the cancer: the poorer differentiation, the more expression (P<0.05). In situ hybridization results showed the positive rate in the carcinoma (54.2%) was higher than normal tissue (27.8%), with statistically significant difference (P<0.05).There were different positive rate in different degrees of differentiation: the poorer differentiation,the higher positive rate, but it had no statistical significance (P>0.05).Conclusions Snai2 could be a biomarker of malignant degree and disease progression,and used as a useful tool for evaluation of prognosis.