Telomeres limit cancer growth by inducing senescence: long-sought in vivo evidence obtained.

Cellular senescence triggered by telomere dysfunction has long been hypothesized to constitute a tumor suppression mechanism. The evidence has come primarily from in vitro cell culture studies, and more indirectly from analysis of tumor specimens. Two recent studies, published in the current issue of Cancer Cell and online at EMBO Reports, provide direct mechanistic evidence in cleverly manipulated mouse cancer models. This work shows that telomere-induced senescence is as effective as apoptosis in reducing cancer incidence and is mediated by the tumor suppressor p53.