KDR and cancer: VEGFR2 signaling is selectively enhanced by its co-receptor neuropilin-1 (NRP1), a transmembrane glycoprotein that lacks kinase activity and whose upregulation in malignant tumors is correlated to aggressive cancer phenotypes (Jubb et al., 2012, Goel and Mercurio, 2013, Lee et al., 2014).