The role of bcl-2 in the progression of the colorectal adenoma carcinoma sequence

Background: The bcl-2 proto-oncogene is a known inhibitor of apoptosis that may allow the accumulation and propagation of cells containing genetic alt erations. Methods: An immunohistochemical study was performed to examine th e role of BCL-2 protein expression in normal colonic mucosa, adenoma, and a denocarcinoma. Results:. BCL-2 was present in the crypt base of normal muco sal glands, while diffuse expression of protein product was observed in 69 cases (65.1%) of adenoma and 29 cases (60%) of adenocarcinoma (p>0.5). A di ffuse expression pattern was often noted in adenomas of the tubular type so litary lesions, small lesions (<1 cm), and those with mild glandular dyspla sia (p<0.05, respectively). There was, however; no apparent difference as t o location, Yamana type of gross appearance, and gender of patients (p>0.05 , respectively). Patterns of BCL-2 expression did not correlate with the bi ologic indicators of adenocarcinoma (p>0.1, respectively). Conclusions: Ou, results support that bcl-2 may play an important role in the early stage o f the adenoma-carcinoma sequence. Down-regulation of bcl-2 is associated wi th the risk of malignant transformation for color ectal adenoma.