Research advances in role of cell-penetrating peptides in tumor

Due to the selective permeability of cell membranes, it is difficult for many macromolecular substances to enter cells. Cellpenetrating peptides(CPPs), which can carry macromolecular substances into cells by means of covalent coupling or non-covalent complex formation, are effective carriers for the intracellular delivery, and they are widely used to deliver proteins, liposomes and nucleotides into the cells. CPPs-based tumor treatment and tumor molecular imaging studies have made a lot of progresses that are reviewed in this article in order to provide insights for the diagnosis and treatment of tumors.