ERBB2 and breast cancer: To identify biological characteristics specific of HER2‐positive BC cells that are addicted to HER2 signaling (Shiu et al., 2014) and responsive to anti‐HER2 therapies, we analyzed the global gene expression profiles of HER2‐positive grafts obtained by injecting transgenic murine mammary cell lines expressing the human d16HER2 variant (MI6) or full‐length–wild‐type HER2 (WTHER2_1) into the m.f.p. of parental FVB mice.