BCL2 and cancer: In mammalian cells, members of the Bcl-2 gene family contains a number of anti-apoptotic proteins, including Bcl-2 and Bcl-xL, which are thought to be involved in resistance to conventional cancer treatment, while the pro-apoptotic proteins from the same gene family, including Bax, Bak and Bad, may induce apoptotic cell death [50].