Expression of p185 and p53 in benign and malignant colorectal lesions

The c-erbB2 gene has been found to be amplified in a number of human adenoc arcinomas, leading to elevated levels of expression of its encoded product, p185. Mutations in the p53 gene are also common in colorectal carcinomas, brain tumours, leukaemia and lymphomas. In this study, p185 and p53 overexpression was analyzed in colorectal adeno mas (22 tubular adenomas and 2 tubulo-villous adenomas) and moderately diff erentiated adenocarcinomas (n = 22) in order to determine whether there was a relationship between these two proteins. The proteins are encoded by two genes located in the same chromosome. p185 and p53 expression was determin ed on tissue sections by immunohistochemical staining procedure. Expression of p185 was significantly higher (p < 0.01) in preneoplastic les ions (95.8% of cases) than colorectal cancer (63.6% of cases). p53 showed a n inverse pattern to p185, being expressed in 58.3% of benign lesions and 7 2.7% of adenocarcinomas. These results confirm that p185 overexpression is associated with the early stages of colorectal cancer, whereas p53 is associated with more advanced stages. Although there was no correlation between p185 and p53 expression i n premalignant lesions and adenocarcinomas, these two proteins have an impo rtant role in the adenoma-carcinoma sequence.