Programmed cell death (PCD) is, in contrast to non-programmed cell death (or necrosis), controlled by active signaling pathways that translate external stimuli in cellular responses. PCD occurs during normal organismal development and underlies tissue homeostasis and organ function. Genetic defects or aqcuired resistance against certain forms of PCD are linked to a wide spectrum of pathophysiological conditions, like tumor formation, inflammatory responses and infection diseases.