Previous studies have reported predominantly nuclear localization of β-catenin as a role for colorectal carcinogenesis. In this study, we examined the immunohistochemical expression of β-catenin and p53 protein in 90 colonic neoplasms {33 carcinomas in adenoma (CIA), 28 high grade adenomas and 29 low grade adenomas}, resected by colonic endoscopy. Out of 33 CIAs, 28 (84.8%) cases showed predominantly nuclear localization of β-catenin, and that was significantly higher than those of both high grade (46.4%) and low grade (13.8%) adenomas. The positiveness of p53 expression in CIAs was 51.5% (17/33), while 17.9% in high grade and 3.4% in low grade adenomas. However, there was no correlation between both protein expressions (
p=0.3472, χ
2 test). The result suggests that nuclear localization and accumulation of β-catenin is earlier event than that of p53 mutation in adenoma-carcinoma sequence, and is useful as a marker in histopathological diagnosis for malignant conversion as well as p53.
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