DNA test could warn of blood cancer five years in advance

Genetics researchers in the US have identified mutations that significantly increase the likelihood that an individual will go on
to develop blood cancer.

The findings were made independently by two research groups
who took the unusual approach of studying DNA from people not known to have cancer
or blood disorders. Focusing on somatic mutations - mutations that cells
acquire over time as they replicate within the body - the scientists identified
a clutch of potentially dangerous changes to genes. When any one of these is present, a
person has a roughly five percent risk of developing some form of blood cancer
within five years.

Dr Siddhartha
Jaiswal, from Massachusetts General
Hospital, primary author of one study, said: 'By the time a cancer has become clinically detectable it has accumulated
several mutations that have evolved over many years. What we are primarily
detecting here is an early, pre-malignant stage in which the cells have acquired
just one initiating mutation.'

Senior author of the second study, Professor Steven
McCarroll from Harvard Medical School, added: 'People often think
about disease in black and white - that there's "healthy" and there's "disease" - but in reality most disease develops gradually over months or years.'

Accordingly, the
findings, published in the New
England Journal of Medicine, show that the frequency of risk-causing
mutations increases with age; they are rare in those under the age of 40, but
become increasingly common and are carried by more than ten percent of those
over the age of 70.

While there's
currently no way to prevent cancer developing for anyone carrying one of these
mutations, Professor McCarroll says that the findings 'demonstrate a way to
identify high-risk cohorts - people who are at much higher than average risk of
progressing to cancer - which could be a population for clinical trials of future
prevention strategies'.

In addition, Dr Benjamin Ebert's team also found that
people with the mutations were more likely to die of any cause over the next
eight years and had more than twice the normal risk of heart and strokes. The scientists say that further
research is required to understand the nature of these associations.