KDR and hepatocellular carcinoma: In contrary, knockdown of Mcl-1 slightly sensitized HCC cells towards inhibition of mTOR by rapamycin (5 nM, 24 h, p < 0.01), selective inhibition of VEGF (Flk-1) and PDGF receptor tyrosine kinases by SU5614 (15 μM, 24 h, p < 0.01) (Fig. 4) and inhibition of the Raf I kinase (p < 0.05, 100 nM, 24 h, Fig. 5A).