TUCAN (Tumor Up-regulated Card-containing Antagonist of Caspase-Nine) is a CARD (Caspase-Associated Recruitment Domains) containing protein that binds and suppresses activation of pro-Caspase-9 and found to be overexpressed in some types of cancers. TUCAN binds specifically to pro-caspase-9 and interferes with its interaction with Apaf-1, thereby suppressing apoptosis signaling in the mitochondrial/cytochrome c pathway.