为探讨Ｐ５３基因突变在大肠癌发生过程中的分子机制，应用聚合酶链反应－单链构象多态性（ＰＣＲ－ＳＳＣＰ）技术对３０例大肠腺癌组织中Ｐ５３基因外显子５、６、７和８分别进行检测。结果发现１６例（５３３３％）大肠癌组织出现了反映Ｐ５３基因突变的异常条带。高、中、低分化腺癌中Ｐ５３基因突变率分别为３３３３％、５０％和７０％。提示Ｐ５３基因突变与大肠癌的发生和发展有关。ＰＣＲ－ＳＳＣＰ能在ＤＮＡ片段的不同部位检测ＤＮＡ多态性和点突变，且灵敏、快速。该方法对大肠癌的基因诊断具有应用价值 In order to investigate the molecular mechanism of P53 gene mutation in colorectal carcinogenesis, polymerase chain reaction-single strand conformation polymorphism (PCR-SSCP) technique was used to analyze the exons 5 and 6 of P53 gene in 30 cases of colorectal adenocarcinoma. 7 and 8 were tested separately. The results showed that 16 cases (53.33%) of colorectal cancer tissues showed abnormal bands that reflected the mutation of P53 gene. The mutation rate of P53 gene in high, moderate and poorly differentiated adenocarcinomas was 3333%, 50%, and 70%, respectively. It suggests that P53 gene mutation is related to the occurrence and development of colorectal cancer. PCR-SSCP detects DNA polymorphisms and point mutations in different parts of DNA fragments, and is sensitive and rapid. This method has application value in gene diagnosis of colorectal cancer