Expression of Her-2 and Ki-67 in Gastric Cancer Formalin Fixed Paraffin Embedded Tissue Blocks and Their Correlation with Histological Grades at the Uganda Cancer Institute Pathology Laboratory

Background: Her-2/neu, the human epidermal growth factor receptor-2, is an oncogene reported to be excessively expressed in gastric cancer. This over-expression is a criteria for treatment with trastuzumab. An antigen linked to nuclear proliferation is Ki-67, and the level of gastric cancer aggression is reflected in its expression. Objective: To determine the expression of Her-2 and Ki-67 in gastric cancer formalin-fixed paraffin-embedded (FFPE) tissue blocks and their correlation with histological grades at the Uganda Cancer Institute pathology laboratory, with each block representing one gastric cancer case. Methods: A laboratory cross-sectional study was conducted among 75 endoscopic gastric cancer patient cases. Each case was assessed utilizing immunohistochemistry (IHC) for the expression of Her-2 and Ki-67. Spearman correlation coefficient was used to ascertain the expression and its correlation to histological grades. Results: The age range of gastric cancer cases was 26 to 80 years, with a mean age of 54. Poorly differentiated histology (43%) was the most profound. Her-2 over-expression was 20%. High Ki-67 expression was 56%, and the low Ki-67 expression was 7%. Her-2 overexpression correlated significantly with moderate differentiation ( rs = 0.336, p = 0.003) and poor differentiation ( rs = − 0.229, p = 0.048). A significant correlation between moderate differentiation of gastric carcinoma with low intensity of Ki-67 staining was noted ( rs = 0.255, p = 0.028). Conclusion: The aggressiveness of gastric cancer may be indicated by the over-expression of Her-2 and a high Ki-67. What This Study Adds: This study provides additional information on the relevance of Her-2 and a high Ki-67 over-expression in diagnosis, prognostic monitoring, and management of gastric cancer in Uganda. Keywords: human epidermal growth factor receptor 2, immunohistochemistry, nuclear proliferation-associated antigen, histology grade