Apoptosis, ap uh TOH sihs, also called programmed cell death, is a process that results in the controlled self-destruction of a cell. This genetically regulated process is an important part of the normal growth and development of organisms. Apoptosis provides for the orderly elimination of unnecessary and worn-out cells and also plays a role in certain diseases. For example, apoptosis can limit the uncontrolled division of cells that leads to cancer.