- Breast cancer determined to be HER2-negative per current American Society of Clinical Oncologists/College of American Pathologists (ASCO/CAP) HER2 Guidelines (If IHC was performed, IHC 0 or 1+; if fluorescence in situ hybridization [FISH] or other in situ hybridization test, dual probe HER2/CEP17 ratio < 2.0 with an average HER2 copy number < 4.0 signals/cell)