CXCR4 and hepatocellular carcinoma: CXCR4-targeted PEGylated poly (lactic-co-glycolic acid) NPs conjugated with LFC131 (a peptide inhibitor of CXCR4), could deliver more sorafenib and metapristone into HCC via specific recognition and binding with transmembrane CXCR4, and resulted in the enhanced cytotoxicity, colony inhibition and apoptosis by regulating more Akt/ERK/p38 MAPK/caspase signaling pathways.