Assessment the of Amplification HER-2/neu Gene by Chromogenic In Situ Hybridization (CISH) Compared to Immunohistochemistry (IHC) Method in Gastric Cancer

Background: Gastric cancer has a high mortality rate and often has a poor treatment outcome. The HER2/neu gene target therapy has been known as a potential way for treatment. Objectives: The goal of our study was assessment the relation between chromogenic in situ hybridization (CISH) and immunohistochemistry (IHC) methods in determining the best diagnostic method for gastric cancer. Methods: In this historical cohort study, 50 gastric cancer samples were analyzed by CISH and IHC. The relation between clinical-pathological parameters of HER2/neu was also analyzed. Alive patients were followed from 2009 through 2012 for the main out-comes (mortality). The results of these two methods, in terms of sex, age, tumor size, grading, staging, tumor location, metaplasia, presence of necrosis and ulceration, vascular invasion, the TNM system, mucin or signet producing adenocarcinoma cells and patient survival rates were compared. Results: There was no significant difference between IHC and CISH regarding the sex, age, tumor size, grading, staging, tumor location, metaplasia, presence of necrosis and ulceration, vascular invasion, the TNM system, mucin or signet producing adenocarci-nomacellsandpatientsurvivalrates. Comparisonof TNMscoresbythesetwomethodsshowednosignificantrelationshipbetween IHC and staging, but a statistically significant difference between CISH and different N staging, (P < 0.05) was assessed. Conclusions: Comparison between IHC and CISH showed the only significant relationship between CISH and different N staging. Therefore, low amplified CISH was a better diagnostic method for gastric cancer, compared to low expression in IHC.