XIAP and cancer: Indeed, while blocking the ErbB2 signaling by trastuzumab leads to apoptosis of cancer cells [116], cardiomyocytes are particularly resistant to mitochondrial apoptosis [105, 106] possibly due to the increased expression of X-linked inhibitor of apoptosis (XIAP) and decreased expression of apoptotic protease activating factor-1 (Apaf1) [117, 118].