**1. Introduction**

Aging is a biological process that consists of a series of structural and functional changes that appear over time and are not a consequence of diseases or accidents. In general, tissues are comprised of specific cells that determine the tissue microenvironment. Various factors affect the cellular environment, such as oxygen pressure, oxidative stress, temperature, and several

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growth factors secreted by cells. Sometimes the cell's microenvironment alters the tissue homeostasis, causing a permissive environment that favors tumor promotion and development. This progressive aging is caused by multiple factors. The following nine characteristics are generally considered to contribute to the aging process: altered intracellular communication, genomic instability, telomere attrition, epigenetic alterations, loss of proteostasis, deregulated nutrient sensing, mitochondrial dysfunction, stem cells exhaustion, and cellular senescence [1].
