Indeed, tumor cells are believed to depend on, or are addicted to, anti-apoptotic Bcl-2 family members, including Bcl-xL [42], providing a selective advantage to cancer cells by allowing them to survive various stressful environments, cell stress phenotypes and/or cell death signals that directly ensue from oncogenic signaling, tumor suppressor deficiency or anticancer treatments [42]. This evidence concerns the gene BCL2 and cancer.