FLT1 and neoplasm: Vascular endothelial growth factor-A expression is elevated in tumours in response to a variety of stimuli (Rak et al, 1995; Dibbens et al, 1999; Igarashi et al, 2002), and its activity is largely restricted to vascular endothelial cells via two high-affinity receptors, Flt-1 (VEGF-R1) and KDR/Flk-1 (VEGF-R2).