PD173074 is a cell-permeable pyridopyrimidine compound that has been shown to act as a potent, ATP-competitive, and reversible inhibitor of FGF and VEGF receptors {IC50 = 21.5 nM for Flg (FGFR1)}. It has been used to inhibit PDGFR and c-Src only at much higher concentration (IC50 = 17.6 μM, 19.8 μM, respectively) and exhibits little effect against EGFR, InsR, MEK, and cPKC even at concentrations as high as 50 μM. It has also been shown to inhibit the autophosphorylation of endogenous Flg (FGFR1, IC50 <5 nM) and overexpressed Flk-1 (VEGFR2, IC50 <200 nM) in NIH3T3 cells in vitro. Inhibition of FGFR signaling impairs angiogenesis as well as self-renewal of stem cells via ERK1/2 activation. Also indicated as an inhibitor of FGFR-3.