CYTOPLASMIC EXPRESSION OF HER2 IN GASTRIC ADENOCARCINOMA: AN UNUSUAL FINDING

Aim : To study the prevalence of HER - 2 expression in gastric adenocarcinoma and its correlation with Helicobacter pylori . Method: 50 gastric cancer biopsies were included in the study. Sections were stained with H& E for morphological details and classified into intestinal and diffuse type gastric adenocarcinoma. Loeffler’s methylene blue was used for identification and grading of Helicobacter pylori . Immunohistochemistry for expression of HER2 protein was done. Patt ern of staining was noted and scoring was done. Monoclonal mouse Anti - HER2/neu (c - erbB2) clone CB11 was used. Statistical analysis was done using chi square test and spearman rank correlation coefficient. P ? 0.05 was taken as critical level of significan ce. Result: Out of 50 cases 9(18%) were intestinal and 41(82%) were diffuse type adenocarcinoma. Helicobacter pylori were seen in 8/9 (88.89%) and 35/41 (85.36%) cases of intestinal and diffuse type adenocarcinoma respectively. HER2 positivity was recorded as membranous, membranous + cytoplasmic and cytoplasmic. 55.56% of cases in intestinal and 73.14% in diffuse type adenocarcinoma showed cytoplasmic ± membranous staining. Expression of HER2 scoring was compared with increasing grades of Helicobacter pylori infection, a significant association ( P <0.05) but weak correlation was found between Helicobacter pylori and HER2 expression. Conclusion : HER2 overexpression is significantly associated with Helicobacter pylori h owever correlation is weak. Predominant cytoplasmic pattern of expression of HER2 in diffuse gastric adenocarcinoma is unusual and needs further investigation