Evaluation of Expression of HER2/neu in Intestinal and Diffuse Type Gastric Carcinomas by Immunohistochemistry

Abstract

Introduction: The management of gastric cancer in advanced stages, which is the second most leading cause of cancer mortality in the world, has evolved very little. Surgical resection remains the mainstay of treatment and can cure patients with early-stage cancer. The survival rate of patients with advanced resectable-gastric cancers, however, remains poor despite new treatment strategies. A better understanding of the molecular basis of cancer has contributed to the development of rationally designed molecular targeted therapies, which interfere with the signalling cascades involved in cell differentiation, proliferation and survival. Aim: To evaluate the expression of HER2 (Human epidermal growth factor receptor 2) by Immunohistochemistry (IHC) in intestinal and diffuse type gastric carcinomas, in and around Kanchipuram, Tamil Nadu, India. Materials and Methods: Fifty cases (31 males, 19 females) were selected which includes 30 cases of resected gastric carcinoma specimens and 20 cases of endoscopic guided biopsies diagnosed as gastric carcinoma in the Department of Pathology, in Meenakshi Medical College and Research Institute (MAHER), Enathur, Kanchipuram, Tamil Nadu which is a teaching medical college and hospital in southern part ofIndia from January 2012 to July 2014 for a period of two and half years. All the cases that were received during the study period that-fulfilled the inclusion and exclusion criteria were included in the study. All cases were analysed for their expression of HER 2/Neu protein antigen by Immunohistochemical staining in this study. The scoring criteria established by an international consensus panel of oncologists and pathologists was followed. Breast carcinoma tissue positively expressing HER2 was used as the positive control. We considered only those tumours expressing 3+positivity as those expressing HER2. Results: HER2 score was significantly higher in intestinal type gastric carcinomas. Of the total 26 cases expressing the HER2 protein, 81% (21/26) were of intestinal type Vs 19% (5/26) that of diffuse types (p=0.007). Also, no statistical difference was found between other variables like age and gender (p=0.098 and p=0.985). Conclusion: This study assessed the expression of HER2 in gastric carcinomas and we found a statistically significant expression in intestinal type gastric carcinomas than the diffuse type gastric carcinomas. There was no significant overexpression of HER2 protein regarding the clinicopathological variables like age and gender.

Keywords

• clinicopathology
• fluorescent in situ hybridization
• histopathology
• lauren’s classification