Aggressive leukaemia puts healthy stem cells to sleep
An aggressive form of leukaemia actually puts healthy stem cells in the bone marrow to sleep, rather than replacing them with cancer cells as was previously thought, reveals a new UK study supported by Cancer Research UK.
This raises the possibility of being able to "reawaken" the sleeping cells, potentially offering an entirely new form of treatment for patients with acute myeloid leukaemia (AML), according to research published in the Proceedings of the National Academy of Sciences (PNAS).
AML is a form of cancer characterised by the rapid growth of abnormal white blood cells that accumulate in the bone marrow and interfere with the production of normal blood cells.
Approximately 2,500 people are diagnosed with the condition in the UK each year, and AML can be fatal within weeks or months if left untreated. Around 2,300 people die each year from the disease.
The research was led by scientists at Queen Mary, University of London, with the support of researchers at Cancer Research UK's London Research Institute.
Professor Peter Johnson, Cancer Research UK's chief clinician, said: "Although major progress has been made in treating AML over the years, there's still an urgent need for more effective treatments to improve long-term survival.
"This study takes us an important step forwards in our understanding of what's going on in the bone marrow of people with AML, an area that we have not known enough about previously, and the challenge now is to turn this understanding into new treatments for patients."
Under normal circumstances, bone marrow produces special stem cells called 'haematopoietic' stem cells, which mature into adult blood cells, including a form called .
But in patients with AML the bone marrow is invaded by immature while blood cells called 'myeloid' cells which are not able to develop into normal functioning blood cells.
That leaves the body short of red blood cells or platelet cells, leading to symptoms such as fatigue, shortness of breath, anaemia, and easy bruising and bleeding.
Patients are also more vulnerable to infection as the white blood cells, which fight bacteria and viruses, are not properly formed.
Dr David Taussig, from the Barts Cancer Institute at Queen Mary, University of London, who led the research, said the study challenged the commonly accepted view of AML.
"The widely accepted explanation has held that AML causes bone marrow failure by depleting the bone marrow of normal haematopoietic stem cells by killing or displacing them," he said..
"However, we have found that samples of bone marrow in both mice models and patients with AML contain the same, or more, of these normal stem cells than usual. So the cancer isn&apost getting rid of them, instead it appears to be turning them off so they aren't going on to form healthy blood cells."
Rather than eliminating the stem cells the cancer appears instead to be turning them off to prevent them from developing into healthy blood cells, he added.
"If we can find out how the cancer cells are doing this, we can look at exploiting it to find ways to wake these stem cells up."
"This is very important as, while the cure rate for younger patients can be around 40 per cent, in older patients it is much lower."
Copyright Press Association 2013