BCL2L1 and plasma cell myeloma: Anti-apoptotic proteins, such as Bcl-2, Bcl-xL, and Mcl-1, have been found to be upregulated in multiple myeloma cell lines, and small molecule inhibitors that target these proteins are in clinical development with the goal of enhancing apoptosis, reversing drug resistance, and improving the survival outcomes of patients with relapsed/refractory multiple myeloma.