Expression, Mutation, And Deletion Of S100A2 Gene In Gastric Carcinoma

Objective To evaluate the possible role mechanism of S100A2 gene in the process ofgastric carcinoma, we detect the levels of mRNA and protein of S100A2 gene in gastric carcinoma. Detecting the mutation and LOH of S100A2 gene in gastric caicinoma is to evaluate the main mechanism of abnormal expression of S100A2 gene in gastric carcinoma Clarity the role of S100A2 gene in the incidence and process of gastric carcinoma in the level of DNA, mRNA and protein of S100A2 gene.Methods Using PCR-SSCP and denaturing PAGE gel electrophoresis we interpret the mutation and deletion of S100A2 gene in the level of DNA in gastric carcinoma. We analyse the expression state of mRNA of S100A2 gene using RT-PCR. Using Western Blotting and S-P immunohistochemical method, we dectect the change of the level of S100A2 protein in the incidence and development of gastric carcinoma, which elucidate the role and molecule mechanism of S100A2 gene in the incidence and process of gastric carcinoma.Results The levels of S100A2 protein were examined in gastric carcinoma andadjacent normal gastric lesions using immunohistochemistry. The S100A2 staining was located on the nuclear membrane and in the cytoplasm. The intensity of staining in morphologically normal gastric mucosa was usually strong. The positive rates of S100A2 protein expression were 52.50% (21/40) in gastric carcinoma and 100% in normal gastric mucosa respectively. The positive rate of S100A2 protein expression in gastric carcinoma was significantly lower than that in normal gastric mucosa (P<0.05). The positive rate of S100A2 expression was 75.00% (12/16) in well differentiated, 53.84% (7/13) in moderate differentiated and 18.18% (2/11) in poor differentiated gastric carcinoma respectively, which indicated the expression of S100A2 protein wasrelated to the degree of differentiation of gastric carcinoma. The positive rate of S100A2 expression in node-positive cases was 29.41% (5/17), which was significantly lower than that in node-negative cases (69.57%, 16/23). The expression of S100A2 was correlated with degree of differentiation of carcinoma and lymph node metastasis.The levels of S100A2 protein were examined in gastric carcinoma and adjacent normal gastric lesions using Western Blotting. The result of Western Blot was the same to that of immunohistochemistry. The levels of S100A2 protein were 1.242±0.221 in normal gastric lesions and 0.538±0.199 in gastric carcinoma respectively. The level of S100A2 protein in gastric carcinoma was significantly lower than that in normal gastric mucosa (P<0.05). The levels of S100A2 protein were 0.833±0.198 in well differentiated, 0.498±0.231 in moderate differentiated and 0.199±0.112 in poor differentiated gastric carcinoma respectively, which indicated the expression of S100A2 protein was related to the degree of differentiation of gastric carcinoma. The levels of S100A2 protein were 0.212±0.159 in node-positive cases and 0.766±0.201 in node-negative cases respectively, which indicated the levels of S100A2 protein were related to lymph node metastasis.The levels of S100A2 mRNA were 1.192±0.254 in normal gastric lesions and 0.502±0.301 in gastric carcinoma respectively. The level of S100A2 mRNA in gastric carcinoma was significantly lower than that in normal gastric mucosa (/*<0.05). The levels of S100A2 mRNA were 0.799±0.390 in well differentiated, 0.550±0.252 in moderate differentiated and 0.311 ±0.188 in poor differentiated gastric carcinoma respectively, which indicated the level of S100A2 mRNA was related to the degree of differentiation of gastric carcinoma. The levels of S100A2 mRNA were 0.266±0.242 in node-positive cases and 0.692±0.212 in node-negative cases respectively, which indicated the levels of S100A2 mRNA were related to lymph node metastasisPCR-SSCP denaturing PAGE gel electrophoresis analysis of the S100A2 gene was performed on gastric cancer and adjacent normal gastric lesions. We screened the microsatellite DNA D1S3498 and the exon 2 and exon 3 of S100A2 coding region. No mutation or deletion was detected in gastric cancer or adjacent normal gastric lesions.