Impact of HER2 copy number in IHC2+/FISH-amplified breast cancer on outcome of adjuvant trastuzumab treatment in a large UK cancer network

摘要

Background: Adjuvant trastuzumab with chemotherapy is standard treatment for HER2-positive breast cancer, defined as either HER2 IHC3+ or IHC2+ and FISH amplified. The aim of this study was to investigate the degree to which HER2 amplification in terms of HER2 gene copy numbers in HER2+IHC2+ cancers affected the outcome in a community setting.