However, based on the hydrophobic grooveobserved in the structures of Bcl-xL48 andthe Bcl-xL/Bak peptide complex,49 it washypothesized that it might be possible to discover a small moleculethat could bind tightly to Bcl-xL and displace Bak and other pro-apoptoticmembers of the Bcl-2 family to cause the death of cancer cells. This evidence concerns the gene BCL2L1 and cancer.