BCL2 and cancer: Bcl-2 family members can be divided into two groups: pro-apoptotic members like Bax, Bad, and anti-apoptotic members like Bcl-2, Bcl-xl, Mcl-1 etc. Cancer cells often evade apoptosis due to the down-regulation of pro-apoptotic Bcl-2 proteins and/or up-regulation of anti-apoptotic Bcl-2 proteins.