Correlation between Frequency of P53 and P21 Proteins with Pathological Parameters in Colorectal Adenocarcinoma

Colorectal cancer is the major and cause of morbidity and mortality throughout the world. Loss of activity of P53 and P21 (WAF1) proteins that belong to the cell cycle regulation family of protein, seems to be important regulatory mechanism of carcinogenesis in colorectal cancer and affected prognosis and resistance to chemotherapy. P21 expressed in P53-dependent and independent pathway. This study was designed to assess P53 and P21 frequency and their correlation with pathological parameters in colorectal adenocarcinoma. This analytical study was done on 70 paraffin preserved colorectal adenocarcinoma samples of patients in Zahedan, Iran who underwent colectomy from 2003 to 2010. Tissue slice was stained and evaluated by method of immunohistochemistry for P53 and P21 protein and evaluated. P53 was expressed in 37(52.9%) patients and P21 was expressed in 33(47.1%). No correlation was found between P53 overexpression and P21 with pathological variables. P21 had a statistically significant association with tumor differentiation (p=0.02). The high frequency of P21 was seen in good differentiated tumors. The results of the study show that P53 mutation plays an important role in the development of colorectal cancer. No correlation between P21 expression and P53 statue supports the theory that P21 induction occurs mostly in P53 independent pathway in colorectal cancer.