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目的：检测 ＡＰＣ（adenomatous polyposis coli）基因在国人大肠肿瘤中的突变情况，探讨ＡＰＣ基因突变与大肠肿瘤病理学特征的关系。同时探讨单链ＤＮＡ 碱基构成与最适ＳＳＣＰ电泳温度的关系。方法：应用聚合酶链反应-单链构象多态（ＰＣＲ－ＳＳＣＰ）技术对６６例散发性大肠癌、17例大肠腺瘤性息肉、４例家族性腺瘤性息肉病（familial adenomatous polyposis,polyposis ,ＦＡＰ）ＡＰＣ基因第１５外显子ＭＣＲ区段的突变进行检测。结果：散发性大肠癌和腺瘤性息肉ＡＰＣ基因突变率分别为２１．２％（１４／６６）和２３．５％（４／１７），两者差异无显著性。散发性大肠癌ＡＰＣ基因突变与肿瘤的位置、浸润深度、组织类型、分化程度、分期以及淋巴结转移无关。ＭＣＲ区段中以密码子１３３７～１４５３区域突变率最高。结论：ＡＰＣ基因突变是大肠肿瘤发生的早期事件。ＳＳＣＰ最适温度与ＤＮＡ片段正链Ｃ/A值成正相关。
OBJECTIVE: To detect the mutation of APC (adenomatous polyposis coli) gene in colorectal tumors in Chinese population and to investigate the relationship between APC gene mutation and pathological features of colorectal neoplasms. At the same time, the relationship between base composition of single-stranded DNA and optimal temperature of SSCP electrophoresis was discussed. METHODS: Polymerase chain reaction-single strand conformation polymorphism (PCR-SSCP) was used in 66 cases of sporadic colorectal cancer, 17 cases of colorectal adenomatous polyps, and 4 cases of familial adenomatous polyposis (polyposis ). Mutations in the MCR segment of exon 15 of the APC gene were detected. RESULTS: The mutation rates of APC gene in sporadic colorectal cancer and adenomatous polyp were 21.2% (14/66) and 23.5% (4/17) respectively. There was no significant difference between the two groups. The sporadic colorectal cancer APC gene mutation has nothing to do with the tumor location, depth of invasion, tissue type, differentiation, stage and lymph node metastasis. In the MCR segment, the highest mutation rate was found in codons 1337 to 1453. Conclusion: APC gene mutation is an early event of colorectal tumorigenesis. The optimum temperature of SSCP is positively correlated with the positive strand C/A value of DNA fragments.