DNA损伤修复能力、p53蛋白及增殖细胞核抗原在大肠癌发生过程中的变化

Alterations in DNA Damage Repair, p53 Protein and PCNA Expression during the Process of Colon Cancer Evolution

通过检测大肠粘膜不同病变上皮细胞的非程序DNA合成（UnscheduledDNAsynthesis，UDS），分析DNA损伤修复能力，以及DNA聚合酶，突变型p53蛋白（以下简称p53蛋白）和增殖细胞核抗原（Proliferatingcellnuclearantigen，PCNA）的表达，分析这些因素在大肠癌发生过程中的变化规律。结果表明，从正常大肠粘膜，癌旁粘膜，散发性大肠腺癌到腺癌，DNA损伤修复能力依次呈逐渐下降趋势，而p53蛋白和PCVA的阳性表达率则随病变向恶性发展而呈逐渐增高的趋势。而且大肠腺癌中的阳性表达率显著高于其它病变组织。但正常粘膜与腺癌组织的DNA聚合酶β活性无显著性差异。分析了这些因素在大肠癌发病中的作用，讨论了它们之间的相互关系，并探讨某些生物标记物在肿瘤检测中的应用意义。

Alterations in DNA damage repair, activation of DNA poly merase, p53 protein and PCNA expression in colonic mucosa with varlous lesions were studied by detecting the unscheduled DNA synthesls to gauge the change pattern and its correlation with carcinogenesis of colon cancer. The results showed that the repair ability of DNA damage declined in the order of intensity from normal colonic mucosa, adjacent tissue of tumor, discrete colonic adenomas and down to adenocarcinoma, but the positive expression of p53 and PCNA increased gradually as the process moved from benign to malignant in the mucosa, and that the expression in the tissue of colonic adenocarcinoma was more pronounced than in the other lesions. There was no significant difference of actlvation of DNA polymerase βbetween the normal mucosa and the adenocarcinoma tissue. It suggests that the pathogenesis of adenocarcinoma may he associated with the cellular crippled repair ability of DNA adamage and that it may be a valuable blologlcal marker to judge the malignant of change adenoma.