Telomeres serve to camouflage chromosome ends from the DNA damage response
machinery. Telomerase activity is required to maintain telomeres. One consequence of
telomere dysfunction is cellular senescence, a permanent growth arrest state. We review the
key regulators of cellular senescence and recent in vivo evidence which supports p53-
dependent senescence induced by short telomeres as a potent tumor suppressor pathway.
The in vivo link between cellular senescence and tumor regression is also discussed. The …