We first evaluated the anti-apoptotic protein dependence of these malignant lymphoid cells by BH3 profiling, which confirmed that both Ri-1 and primary CLL cells were highly dependent on BCL-2 for survival, thereby suggesting that they would likely be sensitive to venetoclax, a drug approved for treatment of CLL (Fig. 3A). This evidence concerns the gene BCL2 and B-cell chronic lymphocytic leukemia.