Stored blood samples show leukaemia developing years before diagnosis

Acute myeloid leukaemia (AML) is an aggressive form of blood cancer that mainly affects older people. Researchers at the University of Cambridge and University College London (UCL) have looked back at how this disease develops in the years, and often even decades, before diagnosis. Their study was published on 11 November 2026 in the scientific journal Nature.

Blood from an old screening study

The researchers used blood from a large British study on the early detection of ovarian cancer. In that study, about 50,000 women gave blood every year for many years, and the samples were stored. A small number of these women later developed AML. The team examined the stored samples of 47 of them, sometimes going back as far as fifteen years before diagnosis. For comparison, they did the same for 46 women who did not develop blood cancer. The women with AML were around 72 years old when they were diagnosed.

Using a very sensitive DNA test, the researchers searched each sample for mutations: small changes in the DNA. They then used a mathematical model to work out when each mutation appeared and how fast the changed cells grew.

All our blood is made again and again by stem cells in the bone marrow. When one of these stem cells gets a mutation that gives it an advantage, a growing group of blood cells with the same change appears. Such a group is called a clone.

Very slow at first, then faster and faster

In two thirds of the women, the first mutation on the path to leukaemia appeared before they turned twenty, so more than fifty years before diagnosis. Such an early clone grew very slowly at first. Each extra mutation of this kind made it grow about two to three times faster. A clone with four of these mutations could double in size within a few weeks.

In at least a third of the women with AML, a single clone had already taken over the blood years before diagnosis. The researchers saw this in none of the women without blood cancer. Using data from the UK Biobank, a large British database of health data, they confirmed that people with such a dominant clone have a much higher risk of AML.

How long the early signs could be seen differed from person to person. In about one in five women with AML, the changed cells could only be found in the blood one to two years before diagnosis. So the warning period can also be short.

A brake in time

Because the clones grow so predictably, a small brake can make a big difference. According to the researchers, slowing down a high-risk clone in the ten years or more before diagnosis could greatly reduce the risk of leukaemia. The team is now studying treatments that could do this. The next step is to test whether this works safely and well in people at high risk.

What does this mean for the road to the singularity?

Ageing in good health starts with seeing earlier what is going wrong. This study shows that the run-up to an aggressive blood cancer often takes decades and follows a measurable, predictable pattern. If regular blood tests and models like these can together point out who is at risk, a doctor may one day be able to step in long before someone becomes ill. That is medicine that prevents disease instead of treating it late.

What is the technological singularity? Read the explanation →