Colorectal adenomas are intraepithelial neoplasms that range from small, often pedunculated polyps to large sessile lesions. Depending on their characteristics (multiplicity, size, histological features, and grade of dysplasia), these lesions can be associated with a substantial risk of recurrence and the development of advanced neoplastic disease.The idea that colorectal carcinoma arises from adenomatous polyp is widely accepted nowadays. A number of studies have been published evaluating the clinical use of p53 and ki-67 immunohistochemical expression as predictors of malignant transformation in colorectal adenomas. Aims of the study: 1- To evaluate The significance of P53 and Ki-67 expression as an immunohistochemical markers in early detection of premalignant changes in different types of colorectal adenomas. - 2
To study the relation of immunohistochemical expression of these two markers with different grades of dysplasia in colorectal adenomas. Patients, Materials, and Methods: The study is reterospective one, in which a total of a fourty seven formalin fixed paraffin embedded polypectomy specimens from patients with colorectal adenomas without concurrent or previous colorectal adenocarcinoma were retrieved from the archival materials of the Gastrointestinal and Hepatic Diseases Teaching Hospital in Baghdad, during the period from January 2009 to March 2010. The histopathological diagnosis had been revised and all cases were stained by immunohistochemical technique with Ki-67 and P53 tumour markers. Values were considered statistically significant when P-value < 0.05. Results: Immunohistochemical expressions of Ki-67 and P53 had highly significant correlation with the size of adenomas (p value = 0.002, 0.001), respectively. Also immunohistochemical expressions of Ki-67 and P53 had a highly significant correlation with the grade of dysplasia in adenomas (p value = 0.006, 0.002) respectively. On the other hand, there were no significant correlations between immunohistochemical expressions of Ki-67 and P53 with the age and gender of the patient, and the type and site of colorectal adenomas (P-value > 0.05). There was a positive correlation between Ki-67 expression and P53 expression in colorectal adenomas, however, it was not significant (P-value = 0.130). Concerning the clinicopathological assessment, the villous adenomas of colorectum is significantly correlated to the grade of dysplasia (P= 0.029). There was no significant correlation between size of colorectal adenoma and the grade of dysplasia, or between site and grade of dysplasia. Also, there was no significant correlation between the type and the size of colorectal adenomas, (p value > 0.05) in all above non significant correlations. Conclusions: •Ki-67 and P53 Immunnohistochemical expressions was significantly correlated with the size and grade of dysplasia in colorectal adenomas. •No significant correlation has been found between immunohisto- chemical expressions of ki-67 and p53 with the age and gender of the patients, and with the site, and type of colorectal adenomas. •There was a positive correlation between Ki-67 and P53 immunohistochemical expressions in colorectal adenomas; but it was statistically not significant.