CXCR4 and hepatocellular carcinoma: The aim of our study was to elucidate the effect of tacrolimus (FK506) and of C-X-C chemokine receptor type 4 (CXCR4), which is a receptor specific to the stromal cell-derived factor-1α (SDF-1α), on growth and metastasis of hepatocellular carcinoma (HCC).