Expression of her2 neu in gastric adenocarcinoma and its co relation with helicobacter pylori

Abstract

Cancer of the Stomach is the 5th leading cause of cancer and the 3rd leading cause of death respectively. Helicobacter pylori, a gram-negative bacteria, found in stomach has been prevalently associated in precancerous lesions and classified as group I carcinogen, especially of intestinal type gastric carcinoma. HER2/neu is a gene which produces HER2 protein, a growth factor of EGFR family and its increased activity is responsible for cell transformation. Pathogenic strains of H. pylori have been found to activate the EGFR via altered signal transduction and gene expression, leading to the development of gastric cancer. The current study seeks to investigate the pattern of HER-2 expression in gastric cancer and its relationship to Helicobacter pylori (HP). RUT was used to screen gastric cancer samples, which were then stained with HandE stain to determine if the cancer was of the intestinal or diffuse kind. Immunohistochemistry was performed for expression of HER2 protein and scoring was done as per standard protocol. Staining pattern of all the samples were identified categorically as membranous, membranous + cytoplasmic and cytoplasmic staining, of which cytoplasmic staining was maximum. Fluorescence in-situ hybridization (FISH) was performed to check for HER2 gene amplification status. Thus all the variables, HER2/neu expression by IHC, H. pylori association and HER2/neu gene amplification were correlated. newlineTrastuzumab act on membrane expressing HER2, and does not act on cytoplasmic expressed HER2. Clinical trials are already being conducted to check efficacy of different drugs as intracellular HER2-targeting compounds. Further gastric cancer-specific protocols for HER2 testing have been developed and standardized using molecular cytogenetic tests like FISH test etc. Hence it is found that cytoplasmic expression of HER2 in diffuse type gastric adenocarcinoma is unusual and predominant which needs future investigations. newline newlineKey words: Stomach, Gastric Adenocarcinoma, HER2/neu, EGFR, Helicobacter pylori. newline newline