Prediction of pCR rates within HER2+ disease may only be reliable once treatment is indicated in accordance to ‘true’ patient HER2 status, with several factors impacting accurate HER2 measurement: Data from the GeparQuattro study revealed discrepancies in HER2 testing between central and peripheral tumour tissue, with greatest sensitivity to anti-HER2 therapy observed in central tumour tissue (pCR probability rate of 46.8% vs. 20.3% in peripheral tissue) [10]. This evidence concerns the gene ERBB2 and neoplasm.