Because VEN is a selective inhibitor of BCL2 protein expressed in AML, other anti-apoptotic BCL2 proteins, such as BCL-xL (74), MCL1 (66, 67, 75), BCL2A1 (76, 77) and BFL1 serve as mediators for primary or acquired secondary resistance to VEN by leukemic cells, via alterations of the apoptotic pathways (5–7, 69). The gene discussed is BCL2; the disease is acute myeloid leukemia.