FGFR2 and breast cancer: FGF10 is overexpressed in ∼10% of human breast cancers23 and increased levels of FGF10 are highly correlated with proliferation rate of breast cancer cell lines and cancer cell invasion.24, 25 It signals through multiple downstream pathways including MAPK and WNT and genes such as FGFR2, CCND1 (MIM: 168461), and TGFB1 (MIM: 190180),21, 24 all known to play key roles in breast cancer.