Strikingly, ERBB2 and GRB7—chromosomally co-localized with ERBB2 and known to be frequently co-amplified with it in HER2-amplified breast cancer [38]—are the two most significantly downregulated genes in the kinase+PTENloss group when compared to wildtype samples (Supplemental Figure 7A). This evidence concerns the gene ERBB2 and breast cancer.