大肠腺瘤样息肉癌变中 ras p21、p53 表达及DNA含量变化

Cellular DNA content, ras p21 and p53 expression in the colorectal adenomatous polyps with cancerous changes

目的：探讨大肠腺瘤样息肉癌变机理。方法：以病理学与ＦＣＭ技术相结合的方法，定量研究４３例大肠腺瘤样息肉（ｃｏｌｏｒｅｃｔａｌａｄｅｎｏｍａｔｏｕｓｐｏｌｙｐｓ，ＣＡＰ）、ＣＡＰ伴有上皮不典型增生及ＣＡＰ癌变细胞的ＤＮＡ含量与癌基因ｒａｓ表达及抑癌基因ｐ５３异常表达。结果：ＣＡＰ细胞ＤＮＡ含量均处在ＤＮＡ二倍体的范围内，而ＣＡＰ伴上皮不典型增生和ＣＡＰ癌变组细胞的ＤＮＡ含量明显高于ＣＡＰ，且为ＤＮＡ异倍体。ＣＡＰ伴有上皮不典型增生及ＣＡＰ癌变细胞突变型ｐ５３蛋白的表达阳性率和表达量亦高于ＣＡＰ。各组病例ｒａｓｐ２１的阳性表达率均在７５％以上，但癌变组ｒａｓｐ２１表达量明显增高。癌变病例则多见ＤＮＡ异倍体及ｒａｓｐ２１和ｐ５３共同表达（１０／１１）。结论：ｒａｓ激活，ｐ５３突变及细胞ＤＮＡ含量的增高，均在大肠腺瘤样息肉癌变中发挥了一定作用。

Purpose To study the carcinogenesis of colorectal adenomatous polys. Methods Cellular DNA contents, oncogene ras and tumor suppressor gene p53 expression at protein level in 43 cases of colorectal adenomatous polyps(CAP), CAP with epithelial atypia and CAP with cancerous changes were studied with classical pathological and flow cytometric(FCM) methods. Results DNA contents of all the CAP cases were in the normal range while that of CAP with epithelial atypia and CAP with cancerous changes were much higher than that of CAP and were in the FCM DNA aneuploidy range. The rate and amount of mutant p53 protein expression in CAP with epithelial atypia and CAP with cancerous changes were higher than those in CAP. Positivity rate of ras p21 expression was quite high in CAP, CAP with epithelial atypia and CAP with cancerous change groups (80%, 75% and 100% respectively), yet the amount of expression in the latter was significantly higher than the former two groups. DNA aneuploid/ras p21 and p53 coexpression was found in 10 of 11 cases of CAP with cancerous changes. Conclusions Thus the results suggest that ras activation, p53 mutation and the increase of cellular DNA content play a certain role in the carcinogenesis of colorectal adenomatous polys.