Apoptotic signaling cascades.

Apoptosis is a form of programmed cell death that results in the orderly and efficient removal of damaged or unnecessary cells, such as those resulting from DNA damage or during development. There are many factors that contribute to this process, each demonstrating specificity of function, regulation, and pathway involvement. The aim of this brief overview is to provide an introduction to a number of these factors as well as the various apoptotic pathways that have been identified.