Abstract

Apoptosis, or programmed cell death, plays a central role in the regulation of both normal and malignant processes. This form of cell death is characterized by DNA degradation into fragments with sizes of one or more nucleosomes and by specific morphologic changes including chromatin condensation and nuclear fragmentation. In the normal context, one role of apoptosis is to ensure that the actual size and constitution of any particular compartment of the body does not exceed the limits dictated by physiological needs. Induction and inhibition of apoptosis are presumably controlled by an intricate network of regulatory signals. This review summarizes the basic mechanisms of apoptosis at the cellular, biochemical, and molecular levels.