Telomere
shortening is involved in the aging process on a cellular level Telomere length
represents our biological age (Image source: @beYouthful247)
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Following a 13-year study, US scientists have identified a
specific pattern of change in the length of a biomarker present in cells, which
occurs many years before a patient begins suffering symptoms of cancer.
A joint team from Harvard
and Northwestern monitored 792 initially cancer-free people for the period, 135
of who were eventually diagnosed with various forms of the illness. In those
years, they constantly monitored their telomeres.
RT.com report continues:
Telomeres serve as a
protective cap on the ends of chromosomes. As people age, and their cells
replicate more and more times, the telomeres grow shorter, until eventually the
cell cannot be multiplied again, and simply dies. They can be both an indicator
of ageing – a sort of internal body clock - and a cause of it, as cells with
worn-down telomeres can malfunction, causing a range of age-related diseases.
Those who were eventually
diagnosed with cancer saw their telomeres depleted alarmingly many years before
it actually developed – with some future patients having telomeres that are
typical for a person 15 years older.
Some of this catastrophic
shortening could be predicted and diagnosed externally – for example simply by
looking at patients who already suffering from inflammations, oxidative stress
and other conditions that age their cells at a rapid rate. But in other people,
who appeared to have few external risk factors for cancer, measuring this rate
could produce a revelatory diagnosis.
But this is not the most
surprising part of the study.
Suddenly, three to four
years before the diagnosis, the shortening would stop, and stabilize – but this
was not good news.
“We found cancer has
hijacked the telomere shortening in order to flourish in the body,” said Dr.
Lifang Hou, a professor of preventive medicine at Northwestern University
Feinberg School of Medicine, and the lead author of the study, which has just
been published in EBioMedicine magazine.
Normally, a cell with a
shortening telomere might be “aged,” but it would at least self-destruct, to
prevent any of the cell abnormalities being allowed to spread through the body.
But in future patients, these cells multiplied, like with the help of the
enzyme telomerase, eventually likely contributing to the cancer.
The study authors say
that previous “snapshot” studies failed to understand the long-term complex
interaction between telomeres and cancer – but that the relationship is clear
and consistent.
“Understanding this
pattern of telomere growth may mean it can be a predictive biomarker for
cancer. Because we saw a strong relationship in the pattern across a wide
variety of cancers, with the right testing these procedures could be used to
eventually diagnose a wide variety of cancers,” said Hou.
To go beyond merely early
testing, scientists now face two separate medical battles.
One is to slow down the
telomere shortening, or whatever underlying conditions may cause it. The other,
according to Hou, is to develop a potential cancer treatment that would force
the afflicted cells to self-destruct instead of making copies, but which would
not merely age and kill off swathes of healthy cells.
According to latest
available World Health Organization statistics, there were over 14 million new
cancer diagnoses in 2012, with more than 8 million people dying of the disease.
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