HER2 expression, gene amplification and chromosome 17 copy number in primary pancreatic adenocarcinoma, metastatic lymph node and metastasis

HER2 expression or gene amplification is crucial for performing targeted therapy. We assessed p 185HER2 (p185) expression, HER2 amplification and copy number of chromosome 17 centromere (CEP 17) in pancreatic adenocarcinoma (PAC). We analyzed 26 tumours at diagnosis, 21 metastatic lymph nodes (mLN) and 38 distant metastases (mTS) by immunohistochemistry and by FiSH. p 185 overexpression was shown in 4% of primary PAC, 6% of mLN and 29% of mTS. Amplification was found restricted to 10% of the mTS and increased CEP 17 in 21% of mTS and 16% of mLN. Overexpression of p 185 was present in all amplified cases but in only 36% of increased CEP/7. In conclusion HER2 amplification and increased CEP 17 were mainly related to mTS or mLN and increased CEP 17 was not always linked to overexpression of p 185.