FLT4 and neoplasm: Among them, VEGF-A and VEGF-C are expressed by the endometrium and VEGF receptor tyrosine kinases, VEGFRs 1 (Flt-1), VEGFR-2 (KDR, Flk-1), and VEGFR-3 (Flt-4), which are exclusively expressed in endothelial cells, hematopoietic stem cells, and tumor cells (7, 8).