Figure 1 shows the intrinsic and extrinsic pathways of apoptosis. BCL-2 and BCL-XL do not affect TRAIL-induced apoptosis in lymphoid cells, but they can prevent or delay apoptosis in nonlymphoid cancer cells (49). BCL-XL and antioxidant enzymes prevent mitochondrial cytochrome C release and reactive oxygen species (ROS) formation in a cell-free reconstitution system caused by caspase-8-mediated BID cleavage and recombinant truncated Bid (tBid) (50). Here, BCL2L1 is linked to cancer.