FLT1 and soft tissue sarcoma: Recently, Antonescu et al reported that human angiosarcomas have unique gene expression profiles when compared to other soft tissue sarcomas [56], with notable enrichment of expression of vascular-specific receptor tyrosine kinases TIE1, KDR (VEGFR2), SNRK, TEK, and FLT1 (VEGFR1), and other genes that are prototypical endothelial markers including EPHA2 and PDGFβ.