Several studies have demonstrated that death signaling is regulated by changes in isoform expression due to alternative splicing, particularly in Fas/CD95 and Bcl-x in T cells and caspase-9 in cancer (Cheng et al., 1994; Goehe et al., 2010; Izquierdo et al., 2005; Shultz et al., 2010). Here, CASP9 is linked to cancer.