Apoptosis: a two-edged sword in aging.

It is now recognized that apoptosis plays an important role in many physiological processes, including aging and age-related diseases. Apoptosis plays both positive and negative roles in aging, and some of these roles are reviewed here. Of particular importance are the roles of apoptosis in reducing cancer incidence, and in promoting neurodegenerative disease. Therefore, the regulation of apoptosis is an inviting target for therapeutic interventions in aging and age-related disease.