In HER-positive breast cancer, the secretion of FGF5 by CAFs leads to FGFR2 activation in cancer cells and acquisition of resistance to trastuzumab and lapatinib (EGFR/HER2 inhibitors) through FGFR2/c-Src-mediated HER2 transactivation [112]. The gene discussed is EGFR; the disease is cancer.