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Published on: December 5, 2017
Changes in HER2 Expression and Amplification Status Following Preoperative Chemotherapy for Gastric Cancer
Sei Shu1,2, Makoto Iimori3, Ryota Nakanishi1
1Department of Surgery and Science, Graduate School of Medical Sciences, Kyushu University, Kyushu University, Fukuoka, Japan.
Background:
It is essential to establish a strategy for second-line treatment for human epidermal growth factor receptor 2 (HER2)-positive gastric cancer; however, HER2 expression status after chemotherapy treatment is not routinely determined.
Materials And Methods:
We analyzed 25 cases of gastric cancer that received preoperative chemotherapy and selected the six pre-treatment samples that were HER2-positive. Pre- and post-treatment tumor samples were examined for HER2 expression, and for HER2, epidermal growth factor receptor (EGFR), and hepatocyte growth factor receptor (MET) gene amplification.
Results:
Three patients had been treated with trastuzumab plus chemotherapy, and three patients with cytotoxic chemotherapy alone. Only one case that had an initial HER2 score of 3+ and had received trastuzumab plus chemotherapy remained HER2-positive after treatment. Decrease or loss of HER2 expression and amplification was observed in the other five patients. Amplification of EGFR or MET was not observed in any pre- or post-treatment specimens.
Conclusion:
Our data suggest that trastuzumab plus chemotherapy or chemotherapy alone may induce loss of HER2 positivity.
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