The finding of increased Pdgfrα phosphorylation is of interest because autocrine Pdgf action is associated with TGF-β-induced epithelial–mesenchymal transition (EMT) in MMTV-Neu mammary tumours and because increased Pdgfrα and Pdgfrβ expression occur in late-stage, invasive human breast cancers [63]. Here, ERBB2 is linked to breast cancer.