[p53 expression in colorectal adenoma and early carcinoma]

Expression of p53 was studied immunohistologically in 25 adenomas, 46 cancers in adenoma, and 18 cancers without adenoma, which were obtained by endoscopic polypectomy or mucosal resection. Positive ratio of p53 expression was 100% in cancer without adenoma, 78.3% in cancer in adenoma, and 48% in adenoma. We divided the positive case of p53 expression to three staining patterns, poorly stained type, focal type and diffuse type. The diffuse type was most of cancer without adenoma. In each diagnostic group there was no significant colleration between sex, age, and shape of polyp and the staining pattern. But in cancer without adenoma, there was significant colleration between size of polyp and the staining pattern, and number of the diffuse type increased as the polyp size was larger. Consequently, it was suggested that p53 takes a role of cancerization from adenomas at every step.