The Value of the Expression of bel-2 and p53 in Colorectal Carcinomas

Chang, Jeong Hwan; Clung, Ki Hwan; Kim, Kweon Chun; Kim, Cheong Yong

Abstract

There are a lots of evidences that colorectal cancer arise as a result of multiple alterations of genes. Many attempts were made to understand the role of oncogenes and suppressor genes as a prognostic indicator, recently. Although histopathologic staging of tumor is the most important prognostic factor up to now, it is not enough to be used with full confidence. Apoptosis or programmed cell death represents a deletion of damaged or natural cell mechanism. The bel-2 proto-oncogene is known as a inhibitor of apoptosis that may allow accumulation and propagation of cells containing genetic alterations. Overexpression of bcl-2 probably plays a role in colorectal carcinogenesis. The aim of this study was to determine bcl-2 and p53 expression in colorectal carcinoma in correlation with apoptosis, clinical parameters, and histopathology, and to test their prognostic significance in patient with colorectal carcinoma. The bel-2 and p53 protein were identified by immunohistochemical staining using monoclonal and polyclonal antibody. The apoptotic index was detetermined by microscopic examination of hematoxyln and rosin-stained sections at x400. The materials subiected to this study were 54 paraffin-embedded colorectal carcinomas, which were collected randomly from January of 1992 to December of 1994 at Department of Surgery, Chosun University Hospital. Of 54 cases, 21 (38.9%) and 22(40.7%) showed positive expression of bel-2 and p53 protein respectively. Mean apoptotic index(AI) was 2.99% in colorectal carcinoma. Bcl-2 expression did not correlated with p53 expression or apoptotic index. Positive expression of p53 or AI was not correlate with any other clinical and pathologic parameters. An inverse correlation was found between bel-2 expression and increased tumor stage or Iymph node metastasis (P<0.05). In conclusion, these results suggest that bcl-2 expression is significant associated with early stage in colorectal carcinoma. But bcl-2 p53 and AI can`t be a independent prognostic factor in colorectal carcinoma. Further investigations to clarity its possible role in controlling the tumor decelopment and growth of colorectal carcinoma are needed.