Oncology reports
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Human epidermal growth factor receptor-2 (HER2) is overexpressed in 15-20% of breast cancer patients and is associated with an aggressive tumor and a poor prognosis. Currently, patients are selected for adjuvant HER2-targeted therapy based on HER2 status by immunohistochemistry (IHC) and fluorescence in situ hybridization (FISH). In this study, we assessed the clinical significance of tissue HER2 status determined by a quantitative immunoassay using ADVIA Centaur. ⋯ The quantitative Centaur assay defined a greater number of patients (100 patients, 26.4%) as HER2-positive than IHC/FISH (63 patients, 16.6%) (P<0.0001). No significant difference in IDFS (P=0.159) and OS (P=0.150) was observed among the four groups of patients. However, in the IHC/FISH-positive group without adjuvant HER2-targeted therapy (group 2), a significantly greater number of events was found compared to the Centaur-positive group without adjuvant HER2-targeted therapy (group 3) for both IDFS (P=0.025) and OS (P=0.020). Quantitative HER2 determination by Centaur did not define a new group of patients eligible for HER2-targeted therapy. Currently, tissue HER2 status defined by IHC/FISH analysis remains the gold standard.