CDKN1B and hepatocellular carcinoma: A negatively charged liposomal delivery system with a mean particle size of 122.5 nm was used for intravenous injection in an HCC xenograft mouse model to deliver anti-miR-221 oligonucleotides and could efficiently increase the expressions of the miR-221 targets PTEN, P27(kip1) and TIMP [318].