Immuno-Histochemical Assessment of HER2NEU Expression in Gastric Adenocarcinoma in North Karnataka, India

Abstract

Background and Objectives: Gastric cancer is the fourth most common cancer worldwide and ranks fifth in India.<br />Surgical resection is curative in early stage gastric cancers. Most of the gastric cancers are diagnosed at an advanced<br />stage necessitating multimodality treatment strategies. Based on the ToGA trial, the international regulatory agencies<br />have recently approved trastuzumab in locally advanced and metastatic gastric and gastroesophageal adenocarcinomas<br />expressing HER2. Since there are limited studies from India and no published data available from this part of North<br />Karnataka, we undertook this study to evaluate the frequency of expression of HER2 in gastric and gastroesophageal<br />adenocarcinomas and to correlate it with various clinicopathological variables. Methodology: The study was conducted<br />in the Department of Pathology, SDM College of Medical Sciences and Hospital, Dharwad, Karnataka from May 2012<br />to January 2016. The samples included both endoscopic biopsies and gastrectomies. Histopathological slides from 70<br />cases were reviewed. Immunohistochemical staining for HER2 was performed in all the cases and Hoffman's gastric<br />cancer scoring system was employed. The results of HER2 expression was correlated with various clinicopathological<br />parameters. Results: HER2 positivity was seen in 16/70 cases (23%). 6 cases (8.5%) were equivocal and 48/70 cases<br />(68.5%) were HER2 negative. HER2 positivity was more common in GEJ cancers and intestinal type of adenocarcinoma.<br />However, it did not correlate with age, gender, grade and stage. Conclusion: HER2 positivity was noted in 23% of the<br />cases. 23.4% of intestinal type and 21.7% of diffuse type were HER2 positive. HER2 positivity did not significantly<br />depend on age, gender, tumour type, grade and stage. Hence, HER2 remains as an independent biomarker and should be<br />tested in all patients of gastric cancer regardless of the clinicopathological findings for offering a personalized treatment.