ERBB2 and neoplasm: The four prototypical tumor subtype centroids (Basal-Like, HER2-Enriched, Luminal A, and Luminal B) were defined by identifying statistically significant (P < 0.001) clusters from hierarchical clustering of the PAM50 genes in 514 samples from the BC no AST, UNC, and WashU cohorts and 24 reduction mammoplasty samples (Fig. 2).