Microsatellite Instability in Intestinal Metaplasia and Gastric Cancer

摘要

Objective: To investigate the changeable patterns of microsatellite instability (MSI) in intestinal metaplasia(IM) and gastric cancer (GC) and the role of MSI in gastric carcinogenesis. Methods: Silver staining single strand conformation polymorphism-polymeriase chain reaction(PCR-SSCP)was used to screen MSI markers at 5 loci in formalin-fixed, paraffin-embedded tissues of GC(n = 30), IM(n = 40) and corresponding normal gastric tissues. Results: The abnormal shifting of the single-strand DNA was identified in 7(23.3%)out of GC and in 8(20%)out of IM samples. Three(10%)tumors and one(2.5%)IM displayed high-frequency MSI(two or more loci altered). Low-frequency MSI(one loci altered)was detected in 4(13.3%)of the tumors and in 7(17.5%)IM samples. GC with MSI was associated with distal location of the tumors but age, sex, differentiation, lymph nodes metastasis and TNM stage (P = 0.044). MSI was more likely detected in moderate-grade IM than in mild-grade IM tissues(34.8% versus 0; P = 0.013); and MSI had a tendency to be easily detected in female with IM. Conclusion: The progressive accumulation of MSI in areas of IM may contribute to GC development, representing an important molecular event in the multistep gastric carcinogenesis.