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背景微卫星不稳是一种重要的基因改变方式,在肿瘤的发生中起重要作用,其发生是由于错配修复基因发生缺陷所致。错配修复基因hM LH1突变在遗传性非息肉性大肠癌中的作用已有报道,但在散发性大肠癌的作用尚缺乏深入的研究。目的探讨错配修复基因hM LH1突变在大肠癌发生中的作用及与微卫星不稳的关系。设计单一样本实验。单位解放军第三军医大学西南医院消化科。材料76例大肠癌及相应正常组织均为2001-01/2003-12西南医院外科手术切除标本,所有患者均无肿瘤家族史,并未接受过放疗和化疗,对实验知情同意。方法采用二维DNA电泳和DNA测序技术检测hM LH1突变;采用聚合酶链反应为基础的方法检测微卫星不稳。主要观察指标①大肠癌hM LH1突变及微卫星不稳检出率。②微卫星不稳与hM LH1突变的关系。结果①76例大肠癌中检出hM LH1基因突变8例,突变率为10.5%,检出微卫星不稳20例,检出率为26.3%。右侧大肠癌hM LH1突变和微卫星不稳的检出率显著高于左侧大肠癌(6/26比2/50,χ2=4.739,P=0.029;11/26比9/50,χ2=5.212,P=0.022),hM LH1突变和微卫星不稳与肿瘤大小、分化程度、组织学类型、浸润深度、淋巴结转移和临床病理分期无显著相关。②将微卫星不稳分为高频率微卫星不稳(≥2个位点)10例、低频率微卫星不稳(仅为1个位点)10例和微卫星不稳阴性56例3组,8例hM LH1基因突变均发生于高频率微卫星不稳组,而低频率微卫星不稳和微卫星不稳阴性组未见有突变者。结论hM LH1基因突变与微卫星不稳多发生于右侧大肠癌,hM LH1突变与高频率微卫星不稳大肠癌的发生有关。
Background Microsatellite instability is an important gene change and plays an important role in tumorigenesis, which is caused by defects in mismatch repair gene. The role of mismatch repair gene hM LH1 mutation in hereditary nonpolyposis colorectal cancer has been reported, but the role of mismatch repair gene hM LH1 in sporadic colorectal cancer is still lack of further study. Objective To investigate the role of mismatch repair gene hM LH1 in the development of colorectal cancer and its relationship with microsatellite instability. Design a single sample experiment. Department of Gastroenterology, Southwest Hospital, Third Military Medical University. Materials 76 cases of colorectal cancer and corresponding normal tissues were all surgically resected specimens of Southwest Hospital from January 2001 to December 2003. All patients had no family history of tumor, no radiotherapy and chemotherapy, and informed consent of the experiment. Methods Two-dimensional DNA electrophoresis and DNA sequencing were used to detect hM LH1 mutation. Microsatellite instability was detected by polymerase chain reaction-based method. MAIN OUTCOME MEASURES ① hM LH1 mutation and microsatellite instability detection rate in colorectal cancer. ② Microsatellite instability and hM LH1 mutation. Results ① The mutation of hM LH1 gene was found in 76 cases of colorectal cancer in 8 cases, the mutation rate was 10.5%. Microsatellite instability was detected in 20 cases and the detection rate was 26.3%. The detection rate of hM LH1 mutation and microsatellite instability in the right colorectal cancer was significantly higher than that in the left colorectal cancer (6/26 to 2/50, χ2 = 4.739, P = 0.029; 11/26 to 9/50, χ2 = 5.212, P = 0.022). There was no significant correlation between hM LH1 mutation and microsatellite instability and tumor size, differentiation, histological type, depth of invasion, lymph node metastasis and clinicopathologic stage. ② Microsatellite instability was divided into 10 cases of high frequency microsatellite instability (≥2 loci), 10 cases of low frequency microsatellite instability (only 1 locus) and 56 cases of microsatellite instability negative 3 cases , 8 cases of hM LH1 gene mutation occurred in high frequency microsatellite instability group, and low frequency microsatellite instability and microsatellite instability negative group no mutation. Conclusion The mutation of hM LH1 gene and microsatellite instability mostly occur in the right colorectal cancer. The mutation of hM LH1 is associated with the occurrence of high-frequency microsatellite instability colorectal cancer.