It has been reported that the co-culture of CLL cells and MSCs provided numerous stimuli of the TME, contributing to the increase in BCL-2 through Notch-1, Notch-2, and Notch-4 signaling, which can partially explain the high levels of the expression of BCL-2 in leukemic cells [14]. This evidence concerns the gene BCL2 and B-cell chronic lymphocytic leukemia.