DELIA HINGANU, CRISTINEL IONEL STAN, CORINA CIUPILAN, ALEXANDRU GRIGOROVICI, VIRGIL BULIMAR, LUCIA CORINA DIMA COZMA, MARIUS VALERIU HINGANU ANATOMICAL AND IMMUNOHISTOCHEMICAL EVALUATION OF COLORECTAL CANCER Colorectal cancer is a malignant disease with high morbidity and mortality. Ki-67 is a marker of cell proliferation associated with a low survival in colorectal cancer patients. Its expression is increased in patients with Dukes C or D colorectal cancer versus those in stage A or B. The purpose of the study is to evaluate the immunohistochemical expression of the Ki-67 marker in colorectal adenocarcinomas. The study was performed on a group of 28 patients diagnosed with rectal cancer. We made the histopathological and immunohistochemical evaluation of patients in the study group. The evaluation was performed on the sections stained with hematoxylin-eosin, and for mucinous forms, on sections stained with alcian blue. The topography of the Ki-67 reaction is strictly nuclear, evident in areas with intense proliferative activity. In cases with a strong positive response to Ki-67, the prognosis is worse, with invasion of the perirectal tissues and metastases. The lack of Ki-67 expression in nearby neoplastic tissues suggests that cancerous tissue proliferates in a pathway that it is not correlated with adjacent tissues. The Ki-67 could be useful in the prognosis of patients with colorectal cancer.