Apoptin induced apoptosis in cancer cells is mitochondrial-mediated caspase-3-dependent, whereby the time point of caspase-3 activation varies from one cell type to another (Danen-van Oorschot et al., 2000; Schoop et al., 2004; Maddika et al., 2005, 2006; Burek et al., 2006; Yuan et al., 2013b). Here, CASP3 is linked to cancer.