Detection of HER2/neu Gene in Pancreatic and Gastric Adenocarcinoma among Chinese Patients

  Objective  To investigate the changes of HER2/neu gene in pancreatic and gastric adenocarcinoma in Chinese patients and to evaluate its roles in targeted gene therapy.

  Methods  The expression of HER2/neu protein was detected using immunohistochemistry, while gene amplifications of HER2/neu were assessed using multi-color fluorescence in situ hybridization (FISH). The samples were paraffin embedded and 10% formalin fixed. They included 81 cases of pancreatic ductal adenocarcinomas with adjacent non-neoplastic pancreatic tissues and 100 cases of gastric adenocarcinomas with adjacent non-neoplastic gastric tisssues.

  Results  Immunohistochemical tests showed that the positive rate of HER2/neu in pancreatic ductal adenocarcinomas and gastric adenocarcinomas was 11.1% (9/81) and 13% (13/100), respectively. FISH showed that HER2/neu gene amplification was detected in 18.5% (15/81) of pancreatic adenocarcinoma cases 11% (11/100) of gastric adenocarcinoma (including all 6 HER2/neu 3 + cases). HER2/neu protein expression and gene amplification were not found in adjacent normal tissues in both arms. Among the pancreatic adenocarcinoma cases, HER2/neu gene amplification was positively correlated with lymphoma metastasis (P=0.001).

  Conclusions  Protein expression is not relevant with gene amplification of HER2/neu in pancreatic cancer. HER2/neu gene amplification may be the major reason for its protein overexpression in gastric adenocarcinoma. HER2/neu gene expression may play an important role in the carcinogenesis of pancreatic and gastric adenocarcinoma. Evaluation of the status of HER2/neu may be helpful to achieve the targeted therapy of pancreatic and gastric adenocarcinoma.