HER2 and Helicobacter pylori Status in Resected Gastric Cancers: A Pathological Study of a Gastroenterological Issue EC01-EC05
Dr. Shrijeet Chakraborti,
Associate Professor, Department of Pathology, Kasturba Medical College,
Lighthouse Hill Road, Hampankatta, Mangaluru-575001, Karnataka, India.
Introduction: Human epidermal growth factor receptor 2 (HER2)/neu is a critical target for gastric carcinoma treatment utilizing trastuzumab. Helicobacter pylori is a well known causative agent of gastric carcinoma.
Aim: To study association of HER2/neu expression with the presence of H. pylori infection in resected carcinoma stomach patients.
Materials and Methods: A cross-sectional study of 85 gastrectomies received in the department from January 2010 to September 2014 was done. HER2/neu was studied using Immunohistochemistry (IHC) and Giemsa stain was used to detect presence of H. pylori. Chi-square test and Fisher’s exact test were used, to test the correlation between the various parameters. A p-value <0.05 was considered significant.
Results: Our study population included 67 (78.8%) males, and 18 (21.2%) females, ranging from 22 to 84 years, mean 57.68±12.12 years. HER-2 expression, graded from 0 to 3± was correlated with location, histologic type, grade, local invasion, metastasis to lymph nodes, TNM tumour staging and H. pylori infection, graded from 0 to 3+ using Giemsa stain. HER2/neu 3+ was observed in intestinal type of gastric cancer (5/55, 9%) only. Scores 2+ and 3+ were more common in H. pylori-negative patients (5/26, 19.2%) than H. pylori-positive patients (4/59, 6.8%) (p=0.02). TNM stage, extent of local invasion and lymph node metastasis in intestinal gastric carcinomas correlated significantly with HER2/neu expression. H. pylori was present in 59 (69.4%) and absent in 26 (30.6%).
Conclusion: H. pylori-negative gastric cancer showed significant immunophenotypic HER2/neu overexpression i.e., H. pylori might protect against HER2 overexpression that correlated significantly with higher TNM stages of intestinal-type gastric cancer. In contrast, H. pylori infection correlated significantly with Lymph-Vascular Invasion (LVI) but was pN1/2+, thereby diminishing prognostic importance. H. pylori induced intestinal metaplasia was not significantly associated with intestinal-type gastric cancer.