Cellular senescence.

Cellular senescence defines a state of stable and generally irreversible proliferative arrest associated with various morphological, structural and functional changes (Figure 1), including enhanced expression and secretion of pro-inflammatory and tissue-remodelling mediators. This state is crucial in tissue physiology and pathology and arises as a response to potentially damaging stress signals. Whether the activation of a senescence state provides benefits or detriments for tissue function and homeostasis is strictly dependent on the context. Cell senescence acts as a potent tumour-suppressive mechanism limiting the proliferation of cells at risk of malignant transformation and supports the repair of acute tissue damage, but also represents a key driver of ageing and age-related diseases.