KDR and neoplasm: Importantly, it has been shown that VEGF receptor (VEGFR) family members are expressed not only in cells of the tumor cell microenvironment (vascular, lymphatic, endothelial and non-endothelial cells) (5) but on various cancer cells such as multiple myeloma, leukaemia, breast, colon, pancreatic (5–8) and leiomyosarcoma cells (2).