CCR1 and hepatocellular carcinoma: CC chemokine receptor (CCR) 1 is highly expressed in human HCC tissues and the C-C motif chemokine ligand (CCL) CCL15/CCR1 axis has an important role in HCC cell migration and invasion through the matrix metalloproteases (MMP) MMP−2 and MMP-9-dependent extracellular matrix degradation [15].