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聚合酶链式反应-单链构象多态性分析法检测大肠腺瘤及大肠癌APC基因突变
对15例散发性大肠腺瘤组织和45例大肠癌组织及其各自的正常肠粘膜组织，进行家族性腺瘤息肉病基因(adenomatous polyposis coli, APC)第15外显子MCR区域的基因突变检测。方法 应用聚合酶链式反应-单链构象多态性分析(PCR-SSCP)技术进行检测。结果 在散发性大肠腺瘤组织中检出突变率为20.0%(3/15)，在大肠癌组织中的突变率为22.2%(10/45)。实验结果表明，APC基因在散发性大肠腺瘤与大肠癌中均有较高突变频率，两者差异无显著性；APC基因突变在大肠癌中与肿瘤的大小、位置、组织分化程度和有无淋巴结转移无关；APC基因第15外显子的MCR区域是该基因突变的集中区域，且以1339～1436密码子区域突变率最高，1260～1359密码子区域突变率最低。结论 证实了APC基因突变发生于腺瘤形成阶段，属于大肠癌发生的早期事件。
Mutations of APC gene MCR region in sporadic colorectal adenomas and carcinomas Wang yan, Liu Shiliang, Hao Dongmei, et al. Department of Gastroenterology, The Third Affiliated Hospital, China Medical University, Shenyang 110021
【Abstract】 Objective Fifteen specimens of colorectal adenomas and 45 specimens of carcinomas and each of their normal mucosa were analyzed for the APC gene exon 15 MCR(mutation cluster region).Methods Gene mutation was examined by PCR-SSCP technique.Results In three out of 15 cases of adenomas(20.0%) and 10 out of 45 cases of carcinomas(22.2%), mutations at MCR was detected. In colorectal carcinoma, APC gene mutation was not related to size, location, histologic features and lymph node metastases. In MCR region, 1260～1359 codons gave a lowest mutation frequency, while 1339～1436 codons showed the highest mutation frequency.Conclusion APC gene mutation detected in colorecral adenomas indicates that the APC gene mutation is an early event in colorectal carcinogenesis. It helps early diagnosis of colorectal carcinoma.
【Subject words】 Colorectal neoplasms Adenoma APC gene Mutation Polymerase chain reaction
现代分子生物学的大量研究揭示，大肠癌在发展过程中涉及到癌基因(K-ras等)的激活和抑癌基因(APC， p53，MCC，DCC等)的失活［1，2］。对家族性腺瘤息肉病基因(adenomatous polyposis coli, APC)的研究发现，该基因在大多数大肠肿瘤中有突变或缺失，与大肠癌的发生密切相关。“腺瘤→腺瘤”模式普遍被认为是70%大肠癌的发展规律，因此，研究腺瘤中APC基因突变对研究大肠癌的发生发展过程具有实际意义。我们用聚合酶链式反应-单链构象多态性分析(PCR-SSCP)技术检测MCR区段的突变，试图探索中国人大肠腺瘤及大肠癌APC基因突变的特点及其与临床关系、病理学特点的相关性，为大肠癌的早期诊断和治疗提供一个分子生物学指标。
