BCL2 and diffuse large B-cell lymphoma: Mechanistically, ABT‐199 combined with Apatinib can synergistically kill DLBCL cells by regulating endothelin‐1 (EDN1) and related MAPK/ERK/MEK pathway to alter the balance of pro‐apoptotic vs. antiapoptotic BCL‐2 proteins without a significant increase in systemic toxicity.