Using DNA samples from research unrelated to cancer, two teams of scientists have uncovered early, pre-cancerous genetic changes in the blood that are linked to increased chances of developing blood cancers such as leukemia, lymphoma or myelodysplastic syndrome. Share on Pinterest Scientists have identified some early gene mutations – believed to start in blood stem cells – that are linked to increased risk of blood cancers like leukemia and lymphoma. The teams believe their findings open new avenues for research into early detection and prevention of blood cancer. The studies – by teams from Harvard Medical School, the Harvard Stem Cell Institute (HSCI), the Broad Institute of MIT and Harvard, and Harvard-affiliated hospitals – are reported in two papers published in the New England Journal of Medicine. Working independently of each other, the two groups of scientists uncovered a detectable, pre-cancerous state in the blood that features mutations that develop in a small number of genes known to be related to blood cancers. The scientists think the mutations – which cells acquire over time – originate in blood stem cells. Steven McCarroll, senior author of one of the papers and assistant professor of genetics at Harvard Medical School, says: “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. These findings give us a window on these early stages in the development of blood cancer.”

Studies looked for early mutations in healthy people’s blood The studies are unusual because they tackled the research from an unconventional direction. Most genetic research on cancer focuses on genomes of advanced cancers to find mutated genes. But in these two new studies, the teams looked at somatic mutations – the copying mistakes in DNA that accumulate over time as cells divide and replicate – in DNA from blood samples of people who did not have cancer or blood disorders. They found that a subset – some, but not all – of mutations known to feature in blood cancers were present in individuals who were 10 times more likely to develop blood cancer later in life, compared with individuals who did not have these mutations. This cluster of pre-cancerous mutations – which is easily detected by DNA sequencing – is rarely found in the blood of people under the age of 40. It becomes more common with age and appears in more than 10% of people over the age of 70. The scientists believe the mutations originate in blood stem cells, spurring mutated cells and their descendant clones to grow faster until they account for a larger proportion of the cells in a person’s blood. They also suspect the early mutations wait for – and team up with – later mutations to drive the cells toward cancer. Most of the mutations occurred in just three genes: DNMT3A, TET2 and ASXL1.