Unsupervised clustering of CPTAC breast tumor proteomes5, using the overlapping high-variance proteins (632 of 1334), identifies three tumor clusters that resemble CoTC1 (basal-like), CoTC3 (luminal A), and CoTC6 (a mix of luminal B and HER2) (Supplementary Fig. 5A, B). Here, ERBB2 is linked to breast neoplasm.