Human epidermal growth factor receptor 2 expression and socio-demographic, clinical, and histopathological characteristics in gastric carcinoma at St Francis Hospital Nsambya, Uganda.

Introduction: Gastric carcinoma is a significant global health burden with diverse clinicopathological features and molecular alterations influencing prognosis and treatment. Human epidermal growth factor receptor 2 (HER2) overexpression is a critical biomarker in gastric carcinoma, guiding targeted therapeutic interventions. This study aimed to assess HER2 expression and its association with clinicopathological characteristics of gastric carcinoma.

Methods: A retrospective cross-sectional study was conducted using consecutive sampling to retrieve gastric carcinoma tissue blocks that met the inclusion criteria. A total of 136 formalin-fixed, paraffin-embedded tissue blocks from patients aged 18 years and above (2013-2023) at St. Francis Hospital Nsambya were analyzed. HER2 expression was evaluated using immunohistochemistry (IHC) with a standardized test kit. Associations between HER2 expression and demographic and histopathological characteristics were analyzed.

Results: Among 136 patients, the mean age was 59.63 years, with 48.53% aged 48-67 years. Most were male (63.24%) and from the Central region (60.70%). The intestinal subtype was the most common (78.68%), with 52.21% of tumors poorly differentiated, and tumors predominantly located in the antrum (32.35%), cardia (30.15%), and body (24.26%). Regarding HER2 expression, 11.76% were positive (3+), 2.21% equivocal (2+), and 86.03% negative (0 or 1+). HER2 positivity was significantly associated with residence in the Western region (aPR = 3.67; 95% CI: 1.33-10.11; p = 0.02) and with mixed-type tumors (aPR = 3.00; 95% CI: 1.70-5.30; p < 0.001).

Conclusion: HER2 overexpression in gastric carcinoma was low. Nevertheless, the findings underscore the importance of routine HER2 testing and access to targeted therapy. Observed associations point to potential high-risk groups warranting further investigation in larger, multicenter studies.