Association between p53 expression and Bcl-2, P-glycoprotein, topoisomerase II alpha, thymidylate synthase and thymidine phosphorylase as potential therapeutic targets in colorectal cancer patients.

We evaluated the expression of molecular markers in colorectal adenocarcinoma in relation to p53 protein expression. Tissue samples of 54 patients with colorectal adenocarcinoma were obtained at surgery at university hospitals in the years 2000-2003. These were analyzed by immunohistochemical techniques using primary antibodies for p53, Bcl-2, P-gp, topoisomerase II alpha and Thymidylate Synthase (TS), thymidine phosphorylase/PD- ECGF (TP) and LSAB detection kit. The highest prevalence of expression among six analyzed markers were P-gp and p53 with 77% expression and the lowest one was Topo II with 35% expression. No clinicopathological significance was recorded in colorectal cancer patients. Several immunophenotypes were observed between p53 and other molecular markers. Additionally the prevalence of lack of expression of Bcl-2, Topo II and TS was higher in p53+ tumors than in p53-tumors. A significant association (p = 0.021) existed between p53/Bcl-2 coexpression and mean age of patients (63.5 [10.1]y vs. 52.3 [15.2] y) and between p53/TP coexpression and sex (66.7% male; (p = 0.022). Overexpression of mutated p53 seen in tumor samples may alter the expression pattern of other molecular markers that are predictors of tumor response to chemotherapy regimens. Age and sex of patients could also affect the p53 related proteins such as Bcl-2 and TP, which can affect therapeutic outcome and disease prognosis. These findings emphasize the importance of tumor immunophenotypes as valuable prognostic or predictive markers in clinical settings.