胃癌及肠化组织的微卫星不稳定性

目的 :探讨微卫星不稳定性 (MSI)在胃癌及肠化组织中的发生规律及其在胃癌发生过程中的作用。方法 :对 30例胃癌、4 0例肠上皮化生的石蜡标本分别提取病变及相应正常组织的DNA ,应用银染PCR SSCP技术检测 5个微卫星位点的不稳定性。结果 :胃癌组织MSI的发生率为2 3 3% ,胃窦癌MSI的发生率显著高于贲门癌 (P =0 0 4 4 )。肠化组织MSI发生率 2 0 % ,MSI全部出现在中度以上肠化组织中 (P =0 0 13) ,且更多见于女性 (P =0 0 4 4 )。结论 :MSI是胃癌多步骤发生过程中的早期分子事件 ,在胃癌的发生中可能具有重要作用。

Microsatellite Instability in Intestinal Metaplasia and Gastric Cancer

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.