Immunohistochemical Study and Clinicopathologic Correlation of Cox-2 and Her-2 Expression in Colorectal Carcinoma: A 5-Year Retrospective Study

ABSTRACT

BACKGROUND: Colorectal cancer (CRC) is the fourth most common cancer in Nigeria, and it affects mostly persons in their middle age. In a bid to gain some insight into the molecular characteristics of CRC in our environment, we set out to investigate the expression of COX-2 and HER-2 among Nigerian subjects. OBJECTIVES: To evaluate the expression of COX-2 and HER2 and determine their correlation with clinicopathologic parameters in surgically resected histologically diagnosed cases of colorectal cancer. METHODS: Fifty-three paraffin-embedded tissue blocks of colorectal resections and corresponding patient information were retrieved from the archives of the Anatomic and Molecular Pathology Department of Lagos University Teaching Hospital.A 4-micron slide section was obtained from each specimen and immunohistochemistry for COX-2 and HER-2 expression was performed. RESULTS: Mean age of cases was 53.9years with an almost equal MF ratio of 1.121. Half of the cases were moderately differentiated adenocarcinoma and 17% were high grade tumors.Eighty three percent of the tumours showed positive cytoplasmic COX-2 expression and extremely low membranous HER-2 positivity was observed in 2%. There was no significant correlation between COX-2 expression and age, gender, tumour location, tumour size, depth of invasion or lymph node status.However, COX-2 expression revealed a significant correlation with tumour grade (p= 0.013). CONCLUSION: This study detects a high COX-2 and low HER2 expression in colorectal cancer using immunohistochemistry,suggesting a possible role for COX-2 in CRC pathogenesis.This report should trigger further investigations of both markers vis-à-vis the management of CRC in our environment. WAJM 2022; 39(11) 1134­1140.