Discovery of genetic link to blood cancers

Mar 22 2009

The study, published in the journal Nature Genetics, has shown that susceptibility to a series of blood cancers, known as myeloproliferative disorders (MPDs), is linked to a particular area of the patient's DNA, which is prone to developing mutations.

Myeloproliferative disorders are characterised by the overproduction of red and white blood cells, which increases the risk of strokes and heart attacks. Many cases of MPDs are caused by a mutation in a gene called JAK2. When the JAK2 gene has mutated, it sends abnormal messages to the blood stem cells to produce more and more blood cells.

Scientists, funded by Leukaemia Research, have found that a particular region of chromosome 9 that carries the JAK2 gene is predisposed to acquiring mutations, but only in individuals with a particular genetic makeup. It is likely that this finding will lead to a much better understanding of how the JAK2 gene mutations happen and why they lead to an increased risk of someone developing an MPD.

The study, carried out at the Wessex Regional Genetics Laboratory in Salisbury and the University of Southampton, has proved that people carrying this mutation-prone region of DNA on chromosome 9 that includes the JAK2 gene have triple the risk of developing an MPD.

The chromosome 9 variant is present in 40 per cent of the UK population but only 1 in 20,000 people develop an MPD each year. Nonetheless, the new research has confirmed that the inheritance of this genetic variant can contribute to inherited susceptibility to develop an MPD.

The study found that the link was especially strong in polycythaemia vera (PV), one of the main three MPDs. Professor Nick Cross, from the University of Southampton who led the research team, says: "This research provides strong evidence that at least half of the cases of PV diagnosed each year are linked to an inherited genetic variant on chromosome 9. Whilst this risk is still very small it nonetheless confirms that individual susceptibility to acquiring cancer-causing mutations is linked to genetic inheritance. Now that we have this evidence we can carry out studies to determine exactly how the variant contributes to this risk."

Dr Shabih Syed, Scientific Director at Leukaemia Research, adds: "This is a very important step forward in our knowledge of the causes of myeloproliferative disorders. It helps us to understand why some people might be predisposed to acquiring genetic mutations that lead to cancers."