[Expression of P53 and heat shock protein in colorectal tumors: an immunohistochemical study]

Abnormality of tumor suppressor gene p53 is supposed to be associated deeply with colon carcinogenesis. We have examined the aberrant expression of the p53 protein in human colorectal cancer or adenomatous tissues immunohistochemically using monoclonal antibody PAb 1801. In microwave-fixed colorectal tissues, p53 was successfully detected in more than 60% of carcinomas. Specific signal for p53 was restricted in the nuclei of cancer cells, while no staining was observed in adjacent normal mucosa. The incidence of p53 expression in colorectal carcinomas was not affected by pathological features such as tumor size, histological grade, nor depth of invasion. In about 10% of colorectal adenomas, weak signal was detected in a few adenomatous glands. Heat shock protein of 72 kDa (HSP72), known to form complex with the mutant-type of p53 in tumor cells, was also detected immunohistochemically in 25% of p53-positive cases. In these cases, high incidence of lymphnodal or distant metastasis was observed, which suggests that expression of both p53 and HSP72 may indicated biological malignancy of the colorectal carcinomas.