MCL1 and acute lymphoblastic leukemia: This increased sensitivity to treatment with the cell-permeable Bak BH3 peptide in this cell line may be explained by the low expression of the antiapoptotic molecules Mcl-1 and Bcl-2 and proapoptotic Bax protein [61] (Figure 1(b)); unlike Ramos cells, CCRF-CEM cells express the Bcl-2 protein; but in pediatric patients with ALL, its presence has been shown to not condition therapeutic drug resistance [62, 63].