BCL2 and B-cell chronic lymphocytic leukemia: In vitro studies had reported that the co-culture of CLL tumor cells and MSCs led to important modifications of gene expression that include an increase in antiapoptotic proteins such as B-cell leukemia/lymphoma-2 (BCL-2), B cell lymphoma-extra-large (BCL-XL), β-catenin, and myeloid leukemia cell differentiation protein 1 (MCL1) [14,19,20,21].