This study showed that specific soluble factors, highly expressed in BC CAFs, conferred lapatinib resistance to different BC cell types: in basal-like HER2-positive cells, HGF-mediated MET activation, while in luminal-like HER2-positive cells, neuregulin 1 beta (NRG1β), a ligand for the tyrosine kinase HER3, favored HER2-HER3 heterodimerization (86). The gene discussed is ERBB3; the disease is breast cancer.