ERBB2 and breast cancer: To determine the prevalence of HER1 and HER1-HER2 dimeric and activated forms in HER2-positive breast cancer, 43 breast tumors that were pre-selected for high HER2 expression by IHC and subsequent scoring using the Allred system [49] (Asterand, Detroit, MI, USA) were analyzed by HER1-HER2 VeraTagTM FFPE tissue assays.