In addition, the microenvironment in the bone marrow of CLL patients is characterized by the increased expression of mRNA and protein levels of the BCL-2 protein family, which is the crucial anti-apoptotic factor that helps maintain CLL proliferation and the basis of its drug resistance tendency so that it can be used as a therapeutic target (Nemkov et al., 2019). Here, BCL2 is linked to B-cell chronic lymphocytic leukemia.