Gene Found to Switch Off Stem Cells During Aging - New York Times: "Biologists have uncovered a deep link between lifespan and cancer in the form of a gene that switches off stem cells as a person ages.

p16INK4a Induces an Age-dependent Decline in Islet Regenerative Potential (Nature)
Increasing p16INK4a Expression Decreases Forebrain Progenitors and Neurogenesis During Ageing

Stem-Cell Ageing Modified by the Cyclin-Dependent Kinase Inhibitor p16INK4a (Nature)The critical gene, already well known for its role in suppressing tumors, seems to mediate a profound balance between life and death. It weighs the generation of new replacement cells, required for continued life, against the risk of death from cancer, which is the inevitable outcome of letting cells divide. To offset the increasing risk of cancer as a person ages, the gene gradually reduces the ability of stem cells to proliferate."