**1. Introduction**

Apoptosis is a type of programmed cell death that is a genetically controlled process of self-destruction. Upon appropriate internal and external stimulus, apoptosis is activated to eliminate the unwanted cells. Hence, damaged cells undergo DNA condensation, membrane blebbing, and cell shrinkage which is the result of activated caspases and proteases [1]. Programmed cell death (PCD) or apoptosis plays an important role to maintain tissue homeostasis. The major aspect of the PCD mechanism is the removal of infected, damaged, or mutation carrying cells (that cause cell-cycle defects). Apoptosis or type I programmed cell death is a well-defined regulated mechanism for the elimination of unwanted cells in the later-period of life. Apoptosis happens in a silent-manner, without causing any damaging effect on the neighboring cells, tissues, and so extinguish stimulation of immunological response [2]. Although, unregulated or deficit form of apoptosis can lead to disease conditions such as cancer and autoimmune diseases [3]. Therefore, understanding the physiological control of apoptosis is crucial for the development of novel approaches to target various diseases. In this chapter, we will provide

a brief introduction of apoptosis, the program cell death pathways, the role of caspases, the role of PCD in cancer, and anti-cancer therapy.
