Correlation between proliferation markers: PCNA, Ki-67, MCM-2 and antiapoptotic protein Bcl-2 in colorectal cancer.

BACKGROUND Colorectal cancer is a major oncological problem. The rate of cancer growth depends on proliferative activity and tumor cell death rate. Therefore, the study objective was to estimate the expression of Bcl-2 as an apoptotic protein representative, as well as other proteins involved in proliferation PCNA (proliferating cell nuclear antigen), Ki-67 and MCM-2 (minichromosome maintaince), and to analyze the correlations between them and chosen anatomo-clinical parameters. MATERIALS AND METHODS The expressions of these proteins were analyzed in 47 patients with pT3, G2 colorectal cancer by immunohistochemistry. RESULTS No association was found between the expressions of Bcl-2, PCNA, Ki-67, MCM-2 and histological type of tumor, distant metastasis, gender or age of patients. However, we observed a correlation of PCNA, Ki-67 and MCM-2 expressions, but not of Bcl-2, in the main mass of tumor in patients with lymph node metastases. Moreover, a very strong relationship was noted between the expression of Bcl-2 and PCNA, Ki-67 and MCM-2 in the main mass of tumor. Conlusion: These investigations seem to suggest that the expression of proliferative proteins (PCNA, Ki-67, MCM-2) in pT3, G2 of colorectal cancer may indicate the development of lymph node metastases and that inhibited apoptosis by Bcl-2 protein can enhance the action of these proteins in tumor progression.