MCL1 and B-cell chronic lymphocytic leukemia: The first synthetic BH-3 mimetic was ABT-737, a small-molecule that binds with high affinity to BCL-2, BCL-X, and BCL-W, but not MCL-1 or A1/BFL-1 (Figure 3), and was shown to efficiently induce apoptosis at sub-micromolar concentrations in a variety of non-Hodgkin lymphoma cell lines (161, 162) and in primary CLL cells (163, 164).