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.