ERBB2 and neoplasm: Interestingly, the detected grouping was not associated with the traditionally used intrinsic genetic PAM50 subtypes (luminal A, luminal B, (HER2)-enriched, basal-like and normal-like), but could be related to the subtypes defined by a reverse phase protein array (RPPA), including four groups similar to the genetic variants (Basal, HER2, luminal A, and luminal A/B groups) and two groups (reactive I and reactive II) characterized by a higher expression of proteins in the tumor milieu.