The synthetic cytotoxic retinoid N-(4-hydroxyphenyl) retinamide (4-HPR) decreased Mcl-1 expression via reactive oxygen species production, resulting in cytotoxicity in acute lymphoblastic leukemia.29 In addition, multiple drugs, such as quercetin,30 gemcitabine,31 actinomycin D,32 and histone deacetylase inhibitor entinostat,33 potentiates cancer cell to ABT-737-induced apoptosis by targeting Mcl-1. Here, MCL1 is linked to acute lymphoblastic leukemia.