Skip to main content
. Author manuscript; available in PMC: 2012 Feb 1.
Published in final edited form as: Clin Geriatr Med. 2011 Feb;27(1):27–37. doi: 10.1016/j.cger.2010.08.006

Figure 1.

Figure 1

Cellular responses to stressors. Stressors (free radicals, DNA damage, nutrient or oxygen constriction, cell injury; represented by the lightening bolt) challenge cellular homeostasis. The cellular response can be senescence, apoptosis, repair, or neoplastic transformation of the cell. Senescence, a tumor suppressive response is associated with an altered secretory phenotype. The controlled cell death of apoptosis can also be tumor suppressive, though many cells, especially immune cells, normally exit through apoptosis. Apoptosis can, however yield tissue/organ atrophy. Repair enables recovery of homeostasis. In some cases apoptosis is a precursor to repair and recovery (dotted line with arrow). Additionally, the senescent cell phenotype is sometimes a precursor/ contributory to neoplasm formation and cancer progression.