This is exemplified by diffuse large B-cell lymphoma (DLBCL) where MCL-1 contributes to intrinsic and acquired resistance to the rationally designed polyselective BCL-2, BCL-XL, and BCL-W inhibitor ABT-737 and the monoselective BCL-2 inhibitor ABT-199 [10, 11]. This evidence concerns the gene BCL2L1 and diffuse large B-cell lymphoma.