HER2 amplification, HER2 overexpression, and TOP2A abnormalities in gastroesophageal cancers: Do they predict responsiveness to epirubicin-based chemotherapy?

e14672 Background: Abnormalities of TOP2A, a major target of anthracyclines, have been reported as positive predictive markers of response to anthracycline-based therapy in breast cancer. We determined abnormalities of TOP2A and HER2, and HER2 protein expression, in a cohort of patients with gastric or gastro-oesophageal junction adenocarcinomas treated with epirubicin-based chemotherapy. Methods: We studied 50 patients that received either adjuvant (74%) or perioperative (26%) epirubicin, cisplatin and 5-fluorouracil. All patients were screened for TOP2A amplification/deletion by fluorescent in situ hybridization (FISH), and for HER2 protein expression by immunohistochemistry (IHC). For each patient at least two paired surgical samples were examined. Tumors exhibiting a HER2 score of 2+ were further screened for gene amplification by FISH. We studied the association of TOP2A abnormalities and HER2 amplification/expression with recurrence free survival (RFS) and overall survival (OS). Results: By IHC, HER...