MCL1 and acute lymphoblastic leukemia: Previous studies have documented synergistic anti-leukemia efficacy of dual BCL-2/XL inhibitor ABT-737 in ALL cells, including xenograft models upon combination with VXL, the regimen used here (Kang et al., 2007); this synergy was attributed to the ability of L-ASP to downregulate MCL-1 protein levels (High et al., 2010).