In multicellular organisms, homeostasis is maintained through a balance between cell proliferation and cell death. Physiologic cell death occurs primarily through an evalutionarliy conserved from of cell suicide termed apoptosis. The decision of a cell to undegoapoptosis can be influenced by a wide variety of regulatory stimuli. Recent evidence suggests that alterations in cell survival contribute to the pathogenesis of a number of human diseases, including cancer, viral infections, a number of human diseases.