ERBB2 and breast cancer: Analysis of BC samples for the presence of theCEP17 duplication at various rates (e.g. > 1.86CEP17/cell, HER2/CEP17 ≥ 2.0) wasperformed by several research groups and yielded contradictory results; eitherthe presence or an absence of a linear relationship between the HER2/CEP17ratio and pCR [11, 13, 14].