Furthermore, Bcl-2-dependent cancer cells can be sensitized towards ABT-199 by the application of BIRD-2154, a BH4-domain inhibitor of Bcl-2 that triggers toxic Ca2+-release events and apoptosis in various cancer cells, including chronic lymphatic leukemia, diffuse large B-cell lymphoma, multiple myeloma, follicular lymphoma, and lung cancer cells86,154–156. Here, BCL2 is linked to B-cell chronic lymphocytic leukemia.