SU4312 is the racemate of (Z)-SU4312 and (E)-SU4312. (Z)-SU4312 inhibits PDGFR and FLK-1 with IC50s of 19.4 and 0.8 μM, respectively. (E)-SU4312 inhibits PDGFR, FLK-1, EGFR, HER-2, and IGF-1R with IC50s of 24.2, 5.2, 18.5, 16.9 and 10.0 μM, respectively.In Vitro: Receptor tyrosine kinases (RTKs) have been shown to be important mediators of cellular signal transduction in cells. Many RTKs have been shown to be oncogene products implicating their role in the transformation process associated with human cancers.