Apoptosis is the process of programmed cell death via a
highly regulated mechanism. There are three major signaling
pathways leading to apoptosis. Firstly, the death receptor
pathway is triggered by the binding of extrinsic signals to
surface receptors including CD95/Fas, tumor necrosis factor
(TNF), and death receptors. This ligand receptor interaction
initiates death signals from the extracellular micro-environment