KDR and hepatocellular carcinoma: With regards to the VEGF family ligand-receptor interactions pathway, VEGFR1 and VEGFR2 are high-affinity receptors for angiogenesis factors and have been found to play key autocrine signaling roles in HCC cell proliferation (de Vries et al., 1992; Quinn et al., 1993; Peng et al., 2014).