Background Gastric adenocarcinoma is the fifth most common malignancy globally, and it is one of the main causes of cancer-related deaths in Uganda. Despite the remarkable improvement in gastric adenocarcinoma treatment modalities, the prognosis of gastric adenocarcinoma remains poor. Several poor prognostic factors have been identified including HER2 protein over-expression in gastric adenocarcinoma. HER2 targeted therapy was indicated by previous studies to prolong the survival of patients with HER2 positive gastric adenocarcinoma. However, the prevalence of HER2 over-expression in Uganda is not known. Objective To study HER2 protein over-expression and its association with demographic characteristics and pathological features of gastric adenocarcinoma as seen at the Pathology of Department, Makerere University. Methods This cross-sectional study was conducted at the Department of Pathology, Makerere University, College of Health Sciences. A sample of 86 archival tissue blocks with histologically confirmed gastric adenocarcinoma from January 2009 to December 2019 was stained by H&E and Immunohistochemistry to assess HER2 over-expression. Data analysis was performed by the use of STATA version 15.0 and a Chi-square test was used to determine the associations. Results The mean age of the patients included in the study was 58.5 years, and most (74.4%) of them were older than 50 years with a slight male predominance (54.7%). Non-cardia tumors were more common (52.3%), and endoscopic biopsies dominated the specimens (62.8%). Poorly cohesive non-signet ring (WHO classification) contributed 47.7% of the tumors, while diffuse or mixed histological subtypes (Lauren classification) were more prevalent (57%). Poorly differentiated adenocarcinomas contributed 66.3% of the tumors followed by moderately differentiated (17.4%) and well differentiated tumors (16.3%). 7 out 86 cases (8.1%) over-expressed HER2 protein. Conclusion The prevalence of HER2 protein over-expression (8.1%) in gastric adenocarcinoma was low in this study, and it is not significantly associated with age, sex, tumor location, the nature of biopsy, histological subtype or tumor grade

show more