BIRC5 and neoplasm: The as-prepared HA/HAase/CS/liposome/shRNA (HCLR) In the HA/HAase/CS/liposome/survivin-shRNA (HCLR) system, HA promoted tumor targeting by virtue of its specific binding to the CD44 receptor on the surface of tumor cells, resulting in much higher tumor accumulation than unmodified liposomes, and prolonging the retention time of liposomes in the blood circulation due to its negative charge.