An expression of p53 marker in colorectal cancer with histopathological correlation

Introduction: Colorectal cancer is the major cause of mortality and morbidity worldwide. Colorectal cancer is the malignant epithelial tumor of the colon and rectum. Incidence in India are quite low about 2 to 8 per 1,00,000. Colorectal cancer develop through a multistep process as characterized by histopathological precursors lesion and molecular genetic alterations including adenomatous polyposis coli 9APC), K-RAS, and p53. The p53 mutations seem to be associated with poor prognosis in colorectal cancer, p53 protein overexpression has been shown to correlate with patient survival. Aim and objectives: To diagnose colorectal carcinomas on H&E sections, to perform and interpret p53 immunostaining on all diagnosed colorectal carcinomas, to infer the rate of positivity and negativity of the P53 mutations in the colorectal lesions, to correlate the p53 mutations with the grade and stage of the colorectal carcinomas, to indicate the prognostic value of p53 mutations in colorectal carcinomas Materials and methods: A prospective study was done for duration of 3 years i.e., 2014- 2016 on in MGM Hospital Warangal. All the colorectal biopsies and resection specimens in all age groups, received in the pathology department during this period were considered after a histopathological diagnosis of the lesion was made, the paraffin blocks of the samples which had met the criteria of inclusion are collected and proceed for immunohistochemical marker. Results: In our study the commonest age group were from 60-69 years with majority of the lesions diagnosed as adenocarcinomas. Males contributed to large number of cases (36) and rectum is the most common site in the present study. Most of cases in this study are of stage IV (AJCC) (30%) and are well differentiated carcinomas (43.3%). p53 overexpression was seen in 40/60 cases. In present study there is statistically significant correlation between p53 overexpression and stage of tumor p value 0.04. In rectal cancers p53 overexpression was more common that colon cancers. Rectum showed 47.5% positivity and left colon 35%. Thus in present study rectal cancers showed high p53 expression. There was no significant correlation of p53 over expression and grade of colorectal Adenocarcinoma but statistically significant correlation was observed with advance stage and p53 overexpression in conventional adenocarcinomas, thus p53 overexpression serves as poor prognostic marker in colorectal adenocarcinomas and it may help to assess the responsiveness of patients to standard chemotherapy. Conclusion: In our study, we noted p53 overexpression in 66.6 % of colorectal cancer. There is an increase in p53 expression with increasing stage of tumor. There is statistically significant correlation between stage and p53 expressions. In conclusion p53 seem to have an important role in the carcinogenesis of colorectal cancers. The evaluation of p53 over expression using a standardized IHC procedure could be clinically useful marker for identification of colorectal cancer patients likely to benefit from Standard chemotherapy regime currently used for this disease.