Patterns in telomeres - those little protective caps that sit at the ends of chromosomes - could one day be used to predict cancer several years before the disease is diagnosed. According to a new study published in EBioMedicine, telomeres can look 15 years older in people who are developing cancer.
Telomeres get shorter every time the cell divides - an inevitable fact of aging. Blood cell telomeres in particular have long been considered a marker of age, but studies trying to connect them with the development of cancer have shown mixed results. Both shorter and longer telomeres have been linked to the disease, while some studies showed no correlation at all. Why the confusion? Turns out, it’s all about timing.
A team led by Lifang Hou of Northwestern University measured telomere length in blood samples from 792 people multiple times over the course of 13 years. Of the initially cancer-free participants, 135 were eventually diagnosed with cancer. This included prostate, skin, lung, bladder, colon, stomach, liver, and pancreas cancer and leukemia.
The researchers found that telomeres aged much faster -- that is, losed length rapidly -- in people who were developing cancer but hadn’t been diagnosed yet. Their telomeres appeared as much as 15 years older than those of people who weren’t developing cancer. However, this accelerated aging didn’t go on and on: it stopped a few years before the diagnosis. This is the first time researchers have described the trajectory of telomere changes over several years in people developing cancer.
“This likely explains why the previous studies have been so inconsistent,” Hou says in a news release. “We saw the inflection point at which rapid telomere shortening stabilizes. We found cancer has hijacked the telomere shortening in order to flourish in the body.”
So, rather than length alone, their new predictive biomarker is a unique telomere pattern that goes like this: a rapid shortening followed by a stabilization three or four years before cancer is diagnosed.
Researchers used to think that, since cancer cells divide and grow rapidly, they would get so short that the cells would ultimately self-destruct. However, the disease actually shuts down that process. If we could figure out how cancer commandeers the cell’s aging process, maybe we can figure out how to force them, and only them, to self-destruct. “Because we saw a strong relationship in the pattern across a wide variety of cancers,” Hou adds, “with the right testing these procedures could be used to eventually diagnose a wide variety of cancers.”
