ABSTRACT
Organismal aging presents with a myriad of characteristics that can be categorized into two basic components: cancer and general organ decline. Cancer is an age-related disease that occurs in many, but not all, individuals in an aging population. In human or animal populations, a wide-range of cancers can be observed. These cancers may share common features, but they also have a different etiology heavily infl uenced by genetics and environment. No matter the etiology, all cancers have lost their ability to regulate cell growth and proliferation and no longer respect their cellular boundaries. These cells are undergoing a process of dedifferentiation and become more embryo-like. Apart from cancer, there is a wide range of examples for general organ/system decline commonly found in aging populations. These include skin and muscle atrophy, osteoporosis, arthritis, cardiovascular disease, cataracts and reduced immune function. Many of these and other symptoms are shared among aged individuals, but virtually no individual carries the entire panoply of the aging phenotype. In this respect, aging is a true stochastic process where chance and variability are the norm (Kirkwood et al. 2011). Unlike cancer, non-neoplastic symptoms
1Department of Molecular Medicine/Institute of Biotechnology, University of Texas Health Science Center, San Antonio, Texas 78245-3702, USA; Email: hastye@uthscsa.edu 2Department of Genetics, Albert Einstein College of Medicine of Yeshiva University, Bronx, NY, USA. aEmail: yousin.suh@einstein.yu.edu bEmail: jan.vijg@enstein.yu.edu *Corresponding authors
of aging are marked not by dedifferentiation and dysregulated cellular proliferation, but instead by loss of function and reduced proliferative capacity. Therefore, cancer and non-cancer, degenerative decline are in a sense two opposing outcomes of the aging process.
