DNA abnormalities could up cancer risk in diabetics

Researchers have found that a type of genetic abnormality that has been associated to cancer is more common in people suffering from type 2 diabetes.

People with type 2 diabetes are already known to have a higher risk of cancer, especially blood cancer types like lymphoma and leukaemia. The new study, led by scientists at the Imperial College London and CNRS in France, suggests that mutations called Clonal Mosaic Events (CMEs) may partly explain why this happens.

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 become 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 tenfold higher risk of blood cancer.

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.

Professor Philippe Froguel, from the School of Public Health at Imperial College London, who led the study, said that the finding could partly explain why people with type 2 diabetes are more likely to get blood cancer. He said that it could have profound clinical implications, and may be useful for doctors to test for CMEs in patients with type 2 diabetes to identify those who have the highest risk of cancer. Mr. Froguel asserted that these patients could be followed up closely to watch for early signs of leukaemia and could start having mild chemotherapy.

The study also found that diabetes patients with CMEs had a much higher rate of complications such as kidney failure, eye disease or heart disease.

The new study has been published in Nature Genetics .