BCL2 and B-cell chronic lymphocytic leukemia: While BCL-2 inhibitors have shown remarkable clinical results in a range of B-cell lymphoid malignancies, response rates to some subtypes of the disease are noticeably higher than those to others (e.g., CLL vs DLBCL) due to the level of initial BCL-2 dependence (intrinsic/innate or primary resistance) and/or development of resistance (acquired or extrinsic resistance) (15).