A water-soluble, amphipathic, 28 amino acid (amino acids 50-77), 2.9 kD fragment peptide (p28) derived from the protein azurin with potential antineoplastic and antiangiogenic activities. Although the mechanism has yet to be fully elucidated, the preferential cellular uptake of azurin-derived cell-penetrating peptide p28 by tumor cells and endothelial cells is likely via caveolae-mediated endocytosis; the C-terminal 18 amino acid residues (50-67) appear to responsible for this preferential uptake. After cell entry, the first 12 amino acid residues interact with tumor suppressor p53 and form a p28:p53 complex, which may result in a reduction of proteasomal degradation of p53, increased p53 levels, and p53-mediated cell cycle inhibition and apoptosis.Azurin is a cupredoxin secreted by the bacterium Pseudomonas aeruginosa. Cell penetrating peptides (CPPs) are cationic and/or amphipathic peptides, typically less than 30 amino acids in length, that can penetrate cell membranes easily and may transport molecular cargo. Check for active clinical trials using this agent. (NCI Thesaurus)