CXCL12 and hepatocellular carcinoma: Sorafenib, a small molecule inhibitor of tyrosine protein kinases, e.g., VEGF receptor 2 (VEGFR2), platelet derived growth factor receptor (PDGFR), and Raf kinases, also promotes TAM infiltration and elevation of CSF-1, SDF-1α/CXCL12 and VEGF in the tumors of hepatocellular carcinoma xenografts [49].