HER2 Expression in Gastric and Gastroesophageal Cancer: Report from a Tertiary Care Hospital in North India.

Despite improvements in chemotherapy, survival of metastatic gastric and gastroesophageal junction (GEJ) adenocarcinoma remains poor. Trastuzumab, a monoclonal antibody targeting the human epidermal growth factor receptor 2 (HER2), has shown promise in improving survival of these patients by a recent large phase III trial. HER2 status in gastric and GEJ cancers, although reported from across the world, is yet unknown in India due to lack of published literature from the country. HER2 status in 70 samples of gastric and GEJ adenocarcinomas (Siewert type III) was evaluated by immunohistochemistry (IHC) in this study using the gastric cancer scoring system. It was also correlated with clinic-pathologic factors. Samples with IHC score 2+ and 3+ were taken as HER2 positive. HER2 overexpression was found in 15 (21.4 %) samples, was significantly (p = 0.006) more common in intestinal type (45 %), but it did not correlate with age, gender, stage, or grade of tumor and did not affect the 2-year disease-free survival. HER2 overexpression is found only in a minority of patients with gastric and GEJ cancers in the Indian population. A large cohort of patients with a longer follow-up will be required to assess for any significant statistical association of HER2 expression with prognosis of these patients.