The rationale was based on the findings of recent studies showing presence of overexpression of mRNA and proteins of vascular growth factors and receptors in angiosarcoma cell lines that include vascular endothelial growth factor (VEGF)-A, VEGF-C, VEGF receptor (VEGF-R1), VEGF-R3, vascular permeability factor (VPF), FLT-A, KDR (VEGF-R2), and v-ets erythroblastosis virus E26 oncogene homolog 1 (ETS-1) [19]. Here, FLT4 is linked to angiosarcoma.