When telomere caps on chromosomes get too short cells usually lose the ability to divide. Telomere shortening is a major cause of aging. But it is also a protective mechanism against cancer. A pattern in telomore length changes is associated with the development of cancer.
CHICAGO --- A distinct pattern in the changing length of blood telomeres, the protective end caps on our DNA strands, can predict cancer many years before actual diagnosis, according to a new study from Northwestern Medicine in collaboration with Harvard University.
The pattern -- a rapid shortening followed by a stabilization three or four years before cancer is diagnosed -- could ultimately yield a new biomarker to predict cancer development with a blood test. This is the first reported trajectory of telomere changes over the years in people developing cancer.
Possibly the stabilization of telomere lengths is due to a mutation that turns on telomerase. That telomerase mutation enables cells to go thru more cell divisions and therefore enables cancer cells in particular to go thru many more cell divisions than healthy cells would be allowed.
Initially, scientists discovered telomeres aged much faster (indicated by a more rapid loss of length) in individuals who were developing but not yet diagnosed with cancer. Telomeres in persons developing cancer looked as much as 15 years chronologically older than those of people who were not developing the disease.
But then scientists found the accelerated aging process stopped three to four years before the cancer diagnosis.
What's the direction of causation for telomere shortening and cancer? Does something accelerate aging and therefore cause more rapid accumulation of genetic mutations that lead to cancer? Or is the cancer process at an early stage causing more rapid telomere shortening?
Here is a familiar argument for long time readers: If we could cure cancer then we could safely increase telomere lengths (given a drug or gene therapy for doing that). Shortening telomere lengths every time a cell divides is an anti-cancer mechanism. But it is also an aging mechanism. The body gives up unlimited cell division because the need to produce more cells for repair is balanced against the threat of death from cancer. Remove the cancer threat and the body could do much more extensive cell replication and slow the rate of aging and even partially reverse aging.
Given a pill to cure cancer I'd then want to take a pill that lengthens my telomeres.
|Share |||Randall Parker, 2015 June 06 12:05 PM|