BCL2L1 and cancer: Inactivating mutations or deletions of pro-apoptotic Bax or Bak are rare, but many cancers, especially those being refractory to therapy, such as colon, gastric and leukemia, overexpress one or more pro-survival family members, including Bcl-2, Bcl-xL and Mcl-1 [45,46,47,48,49].