Department of Medicine, Stanford University School of Medicine, Stanford, CA 94305, USA.
Data from mouse models and from human cancers have supported the idea that telomere shortening leads to chromosomal instability and epithelial carcinogenesis. In this issue of Cancer Cell, Else et al. demonstrate that telomere uncapping-altering a protein that protects chromosome ends without shortening telomeres-also results in epithelial cancers.