They have been dubbed the “fountain of youth”. Now scientists have shown that telomeres are also staging grounds for the deadliest skin cancers. The biggest analysis of the genetic risk factors for melanoma has confirmed telomeres play a role in the killer skin tumours. The international study, published in the journal Nature Genetics, reinforces a theory that long telomeres allow further time for cells to mutate.
The findings have emerged from Australian-born telomere pioneer Elizabeth Blackburn. Professor Blackburn won the 2009 Nobel Prize for Medicine after discovering telomerase, the enzyme that replenishes telomeres.
On an Australian speaking tour, she wound up explaining how healthy telomeres helped ward off aging and disease. Short telomeres have been linked to slow healing, premature aging, cardiovascular disease and common cancers. A small industry has sprung up focused on measuring telomere length as an indicator of health and biological age, with products advertised on the internet promising to slow down the aging process by preventing your telomeres from shortening.
Professor Blackburn told The Australian that long telomeres had now been implicated in a subset of “really nasty” cancers, including melanoma, brain tumour and lung cancer.
“There’s no magic pill to push telomere maintenance, because the indications are that it will push you into disease, particularly cancer,” she said. “There’s nostrums (being advertised) online, and I wouldn’t touch them with a barge pole. You just don’t know if you’re pushing up telomere maintenance in a good or bad way.”
The new study involved 10 Australian institutions and teams from the US, Europe, China and Israel. It analyzed 11 genomic studies involving almost 16,000 melanoma sufferers and more than 26,000 healthy “controls”.
The researchers identified five regions of the genome not known to play a role in melanoma, as well as confirming 2014 evidence implicating telomeres. “We now know of 20 common genetic risk factors, and 12 of these are clearly related to telomere length, pigmentation or the number of moles an individual has,” said co-lead author Mark Iles from the University of Leeds in Britain. “These last two factors are long-established as indicators of risk for melanoma. This reinforces the message that anyone with pale skin and many moles should take extra care.”
The study’s other lead author, Matthew Law of the QIMR Berghofer Medical Research Institute in Brisbane, said the findings did not change the basic advice to cover up and have suspicious moles checked. He said hereditary factors accounted for only about half the risk of contracting melanoma, and only about one-fifth of this risk had been associated with specific genetic regions. Dr Law said the results raised hopes that drugs could be developed to prevent melanomas or treat existing tumors. He said the ideal scenario was that medications for other diseases could be “retargeted” to fight melanoma. This would reduce the need for expensive and time-consuming clinical trials.
Dr Law said the findings contradicted the assumption that short telomeres were a problem. “Biology is so complex that whenever you start adjusting something, it can have unexpected effects downstream,” he said.
Professor Blackburn said there was strong evidence associating short telomeres with mass killers such as heart disease and more common cancers. She said people trying to tweak telomeres to reduce melanoma risk could end up stripping themselves of protection against the “huge majority” killers.
“It’s a sort of trade-off between too much and too little,” she said. “This is the way humans are built. It’s just our bad luck.”