A type of genetic abnormality linked to cancer is more common in
people with type 2 diabetes than the rest of the population, a new
study has found.
People with type 2 diabetes are already known to have a higher
risk of cancers, especially blood cancers like lymphoma and
leukaemia. The new study, led by scientists at Imperial College
London and CNRS in France, suggests that mutations called clonal
mosaic events (CMEs) may partly explain why this
is.
CMEs are defects that result in some cells having extra copies
or missing copies of large chunks of DNA. They are very rare in
young people but more common as we get older. Among those aged over
70, around one in 50 people have some of these mutations. Research
published last year found that people with CMEs have a 10-fold
higher risk of blood cancers.
In the new study, researchers looked for CMEs in blood samples
from 7,437 participants in genetic studies in Europe, including
2,208 people with type 2 diabetes. They found that CMEs were four
times more common in people with type 2
diabetes.
"Type 2 diabetes is a disease that accelerates ageing, so we
wondered if it would make people more likely to have these genetic
defects that are associated with ageing," said Professor Philippe
Froguel, from the School of Public Health at Imperial College
London, who led the study.
"This finding may partly explain why people with type 2 diabetes
are more likely to get blood cancers. It could have profound
clinical implications. It may be useful for doctors to test for
CMEs in patients with type 2 diabetes to identify those who have
the highest risk of cancers. These patients would be followed up
closely to watch for early signs of leukaemia and could start
having mild chemotherapy."
They also found that diabetes patients with CMEs had a much
higher rate of complications such as kidney failure, eye disease or
heart disease.
The paper, Association between large detectable clonal mosaicism and type 2
diabetes with vascular complications, is published inNature Genetics.