CASP9 and B-cell chronic lymphocytic leukemia: Venetoclax and SRF231 co-treatment activated two distinct cell death pathways in both Ri-1 and primary CLL cells, including increased caspase 9 activity and cleaved caspase 3 (apoptosis) by venetoclax and p-MLKL (necroptosis) by SRF231 (Fig. 3C and D).