BCL2L1 and neoplasm: Of note, the A-1331852 efficacy of sensitizing tumor cells against regorafenib was higher than siBCL-xL reduction, probably due to A-1331852’s powerful inhibition (Ki < 0.04 nM) of BCL-xL compared with the reduction obtained, up to 80% (Figure 2F), with the two siBCL-xL tested.