ABSTRACT
OBJECTIVE: To investigate the role of microsatellite instability (MSI) in the pathogenesis of gastric carcinoma and its relationship with the expression of hTERT gene. METHODS: 75 cases of gastric carcinoma and paired normal control tissues were included in this study. MSI of BAT-25, BAT-26, D5S346, D17S250 and D2S1235 were detected by PCR, native polyacrylamide gel electrophoresis, and silver staining while the expression of hTERT was localized by immunohistochemistry at the same time. RESULTS: MSI positive rates of BAT-25, BAT-26, D5S346, D17S250 and D2S123 were 14.7%, 12.00%, 26.67%, 16% and 21.3%. MSI was obviously related with lymph node metastasis and pathologic stages respectively (P<0.05), but not with age, gender, histologic type, or infiltration depth (P>0.05). hTERT was not expressed in normal gastric mucosa, but in intestinal metaplasia, dysplasia, and gastric carcinoma. The positive rate of hTERT was 76% (57/75) in 75 cases of gastric carcinoma tissues. The expression of hTERT was obviously related to histological type (P<0.05), but not to age, gender, lymph node metastasis, depth of invasion, or staging, respectively (P>0.05). The positive rate was higher in poorly differentiated cases than in moderately and well differentiated cases (P<0.05). MSI accounted for 28.1% of 57 hTERT positive cases while MSI accounted for 72.2% in 18 hTERT negative cases. Spearman rank correlation analysis showed that MSI was negatively related to hTERT expression (r=0.387, P=0.001). CONCLUSION: MSI may play an important role in the pathogenesis and progression of gastric carcinoma by affecting the expression of TERT gene.
