XIAP also known as AIP-3 is a protein that belongs to a family of apoptotic suppressor proteins. XIAP plays a crucial role in regulating apoptosis by inhibiting activated caspase-3, which is essential for cell survival during stress conditions. This function is particularly important in cancer biology, as many tumors exploit XIAP to evade programmed cell death, allowing for uncontrolled cell proliferation. Additionally, XIAP interacts with other members of the inhibitor of apoptosis protein family, such as survivin, which is expressed during the G2/M phase of the cell cycle and is involved in mitotic spindle assembly. XIAP′s ability to modulate apoptotic pathways makes XIAP a significant target for therapeutic interventions aimed at restoring apoptosis in cancer cells.