Dual-color Silver-enhanced In-situ Hybridization For Determination Of HER2Gene Amplification In Gastric Carcinoma And Clinical Significance

ObjectiveTo investigate DSISH (dual-color silver enhanced in—situ hybridization) and IHC (immunohistochemistry) results of consistency in gastric cancer HER2gene amplification and expression and the correlation between HER2gene status in gastric carcinoma and the clinical pathological parameters and to evaluate the feasibility of DSISH.Methods IHC was used to detected HER2protein and DSISH was used to detected HER2gene amplification in230cases of gastric cancer.ResultsAmong230cases of gastric carcinoma, the expression of HER2(3+) was31cases by IHC, HER2protein positive expression rate was13.5%(31/230); the amplification of HER2was43cases, HER2gene amplification rate was18.3%(43/230).23cases were17th chromosome polyploidy, among which5,1and9cases were strongly, moderately and weak positive in IHC respectively, the percentage of17th chromosome polyploidy was10%(23/230). HER2gene status in gastric cancer were significantly correlated with degree of differentiation of gastric cancer (P<0.05), lymph node metastasis (P<0.05), but not with patient’s age, gender, site of gastric cancer (P>0.05), the depth of tumor invasion (P>0.05), nerve, vascular invasion (P>0.05). The overall concordance in our investigation between IHC and DSIDH of HER2is93.5%(201/215), with a high degree of consistency (Kappa coefficient0.767, P<0.001).Conclusions There are HER2protein overexpression and HER2gene amplification in gastric cancer. HER2can be as the reason for targeted-therapy. DSISH as a new gene amplification detection technology has its obvious advantages, can be applied to detect the HER2gene status in gastric cancer. These cases need further detection by DSISH when the HER2protein expression moderately. In addition, while detecting the status of HER2gene, the effect of17th chromosome polyploidy should be considered.