Prevalence of p53 and p21 Expression in Colorectal Cancer: A Histopathologic Study from Iran

Disruption or inactivation of p53 and p21 proteins’ expression may lead to colorectal adenocarcinoma. In addition, prognosis of the patients and their response to chemotherapy depends on these proteins’ expression. Therefore, in this study, we attempted to evaluate the prevalence of these proteins’ expression in colorectal adenocarcinoma and their correlation with pathological parameters. We have studied immunostained-preserved tissues of 70 patients with colorectal adenocarcinoma who have tolerated colectomy from 2003 to 2010. Specimens were evaluated for the expression of p53 and p21 proteins. Over-expression of p53 and p21 proteins were seen in 52.9 and 47.1% of the patients, respectively. There was no correlation between over-expression of p53 and p21 with the pathological parameters. A significant association was found between p21 and tumor differentiation (p<0.05). High expression of p21 was also found in well-differentiated tumors. Also, the absence of correlation between p21 expression and p53 status was found (p<0.05). The results of our study indicate that p53 protein over-expression plays an important role in progression of colorectal cancer. p21 may also play an important role in differentiation of tumor cells. It also seems that p21 expression induction occurs in a p53-independent pathway in colorectal cancer.