**Author details**

Yasuhiko Hirabayashi

*Department of Rheumatology, Hikarigaoka Spellman Hospital, Japan Department of Hematology & Rheumatology, Tohoku University Hospital, Japan* 

## **8. References**


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**Chapter 4** 

© 2012 Martínez-Lacaci et al., licensee InTech. This is an open access chapter distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/3.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

© 2012 Martínez-Lacaci et al., licensee InTech. This is a paper distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/3.0), which permits unrestricted use,

distribution, and reproduction in any medium, provided the original work is properly cited.

**Cell Death and Cancer,** 

**Novel Therapeutic Strategies** 

Silvina Grasso, M. Piedad Menéndez-Gutiérrez, Estefanía Carrasco-García, Leticia Mayor-López, Elena Tristante, Lourdes Rocamora-Reverte, Ángeles Gómez-Martínez, Pilar García-Morales,

Additional information is available at the end of the chapter

**1.1. History, definition and classification** 

http://dx.doi.org/10.5772/51285

**1. Introduction** 

José A. Ferragut, Miguel Saceda and Isabel Martínez-Lacaci

triggering an immune response, avoiding thus tissue damage [3].

Life and death are essential parts of the natural cycle of all multicellular organisms. In metazoans, somatic cells divide normally during the process known as mitosis. Cell proliferation is tightly controlled, according to the organism needs. An increase in the number of cells takes place during growth and when one of these cells finishes its physiological function or detects DNA or cell damage, it undergoes a physiological process known as apoptosis that induces its own death. In humans about a hundred thousand cells are formed every second through mitosis, while a similar number is destroyed by apoptosis [1]. This dynamic balance between proliferation and cell death is known as homeostasis. If altered, different pathologic processes such as carcinogenesis can take place. Besides its role in embryonic development, homeostasis maintenance and aging, apoptosis is also a defence mechanism by which infected, injured or mutated cells as a result of irradiation or chemotherapeutic drugs are eliminated. This type of cell death involves the activation of an evolutionary conserved and tightly regulated intracellular machinery that requires energy consumption [2]. An important feature of apoptosis is that the cell is eliminated without

The term **apoptosis** to describe cell death was introduced by Kerr and colleagues in 1972 [4], from the Greek term "appo-teo-sis" which means "falling off" (as in leaves from a tree or petals from a flower). Apoptosis has been used as a synonym of programmed cell death and
