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.