BACKGROUND: The objective of this study was to investigate if there are any differences in tissue expression of p53 protein according to tumor location in colorectal cancer patients. METHOD: One hundred colorectal adenocarcinoma patients (54 women) of mean age 59.8 years were studied. Expression of p53 protein was analyzed through immunohistochemistry, using anti-p53 monoclonal antibodies and the streptavidin-biotin-peroxidase technique. Correlations between tissue expression of p53 protein and the following variables were investigated: gender, age, histological grade, histological type, tumor size, TNM staging, depth of intestinal wall invasion, lymph node involvement, angiolymphatic invasion, and proximal or distal tumor location in relation to the splenic flexure. For statistical evaluation of the relationship between p53 protein expression and these variables, the chi-squared test was used, with the significance level set at 5% (p<0.05). RESULTS: There was positivity for p53 protein in 75% of the cases. Among the different variables considered, a greater tendency towards expression of the mutant protein was found in relation to age (p=0.001), a histological grade (p=0.001), a histological type (p=0.001), advanced TNM staging (p=0.001), deeper depth of colon wall invasion (p=0.001), lymph node involvement (p=0.001), angiolymphatic invasion (p=0.02) and distal location to the splenic flexure (p=0.001). However, there was no relationship with gender (p=0.49) or tumor size (p=0.08). CONCLUSION: The results from this study allow the conclusion that the expression of mutant p53 protein occurs more frequently in tumors located distally to the splenic flexure.
Colonic neoplasms; Tumor markers, biological; Tumor suppressor protein p53; Genes, p53; Immunohistochemistry
