Genetic analysis in dysplasia and carcinoma accompanied with longstanding ulcerative colitis

Vogelstein等。1988年提出了结直肠癌的多步骤癌变模型，许多与结直肠癌相关的遗传异常已被许多研究所注意到。另一方面，随着长期溃疡性结肠炎（UC）患者的增加，K-ras和p53基因突变在UC并发症的结直肠癌中得到了研究，尽管这个问题目前还存在争议。我们通过对癌症合并长期溃疡性结肠炎患者ras基因突变、p53蛋白过表达及密码子201 DCC多态性的研究来阐明异型增生的诊断，发现在难以判断是否再生的结肠炎异型增生中，合并癌症时p53免疫染色阳性率高，而在DCC和ras异常情况下，异型增生上皮与再生上皮无差异。ras基因的突变极低。综上所述，我们的研究提示，尽管DCC多态性和ras基因点突变的检测对慢性溃疡性结肠炎的诊断没有帮助，但在结肠镜监测中发现的p53阳性患者可能存在癌症并发症。

Vogelstein et a1. proposed a multistep carcinogenesis model of colorectal cancer in 1988, and a number of genetic abnormalities associated with colorectal cancer have been noted in many institutes. On the other hand, with the increase in patients contracting ulcerative colitis (UC) for a long period, mutation of the K-ras and p53 genes in colorectal cancer with a complication of UC,has been investigated, although this issue now will be controversial. we investigated the ras gene mutations, overexpression of p53 protein and DCC polymorphism in codon 201 in cancer complicated with longstanding ulcerative colitis to elucidate the diagnosis of dysplasia and found that in dysplasia of colitis which are difficult to judge whether to be regenerative, p53 immunostaining was positive at a high rate if complicated with cancer but in DCC and ras abnormalities, no differences between dysplasia and regenerative epithelia were detected. Mutaions of ras gene were extremely low.In conclusion, our studies suggested that p53 positive patients found in surveillance colonoscopy are likely to have complication of cancer although the detection of DCC polymorphism and point mutation of ras genes was not useful for the diagnosis of dysplasia accompanied with longstanding ulcerative colitis.