The most effective Bcl-2 inhibitors ABT-737 and its analog ABT-263 target Bcl-2 and Bcl-xL (Oltersdorf et al., 2005; Yip and Reed, 2008); however, only weakly inhibited Mcl-1 thus are not effective against cancers with elevated Mcl-1 levels (van Delft et al., 2006). Here, MCL1 is linked to cancer.