HIPK2 and neoplasm: As a proof of principle, HIPK2 knockdown impairs p53 function, induces chemoresistance, angiogenesis, and tumor growth in vivo, on the contrary, HIPK2 overexpression activates apoptotic pathways, counteracts hypoxia, inhibits angiogenesis, and induces chemosensitivity both in p53-dependent and -independent ways.