Immunohistochemical expression of clusterin in colorectal carcinoma

Background and objective: Colorectal cancer is a heterogeneous malignancy characterized by a wide range of genetic and epigenetic alterations. Clusterin is a heterodimeric glycoprotein widely expressed in a variety of tissues and secreted in many body fluids. Increased clusterin expression has been reported in the normal colonic mucosa, benign polyps, and colorectal carcinoma. This study aimed to detect the frequency of the clusterin immunoexpression in colorectal carcinoma and determine its association with some clinicopathological parameters. Methods: Sixty formalin-fixed paraffin-embedded sections of colorectal adenocarcinoma were obtained and randomly selected from the histopathology laboratory at Rizgary Teaching Hospital and some private histopathology laboratories in Erbil city over two years between December 2016 and December 2018. All patients had been diagnosed to have primary colorectal adenocarcinoma and had undergone surgery. The clinicopathological characteristics of the tumors were revised, and the specimens were analyzed immunohistochemically using anticlusterin mouse monoclonal antibody. Results: Twenty eight cases (46.6%) were labeled as clusterin positive, while 32 cases (53.4%) were negative for clusterin expression. Clusterin expression was significantly associated with the tumor type (Non-mucinous) (P = 0.01) and tumor grade (well to moderately differentiated) (P = 0.03). At the same time, no significant association was found between clusterin immunoexpression and other clinicopathological characteristics like age, gender, tumor site, and tumor stage. Conclusion: Our study indicated that clusterin is overexpressed in some colorectal carcinomas and is significantly associated with histological type and grade. These results suggest that clusterin may play a role in colorectal carcinogenesis. Further studies are required to understand the possible mechanism of clusterin association with carcinogenesis and cancer progression. Keywords: Colorectal cancer; Clusterin; Immunohistochemistry.