Researchers have identified four new regions of the genome linked with an increase in susceptibility to chronic lymphocytic leukaemia (CLL). The findings suggest that this common type of blood cancer may develop partly as a result of faults in telomeres, sections of DNA that are vital to healthy cell division.
Scientists at The Institute of Cancer Research, London, analysed the genomes of 1,739 patients with CLL and 5,199 healthy adults. The study linked four single nucleotide polymorphisms (SNPs), small inherited differences in DNA, with susceptibility to CLL.
The research, published online in the journal Nature Genetics, was principally funded by blood cancer charity Leukaemia & Lymphoma Research, with additional support from Cancer Research UK and the Arbib Fund.
CLL is the most common form of leukaemia in western countries, with over 3,000 people diagnosed in the UK each year. It is a slowly progressing and currently incurable form of cancer that affects blood-producing cells in the bone marrow. Close relatives of CLL patients are at eight times higher risk of being diagnosed than the general population.
Study leader Richard Houlston, Professor of Molecular and Population Genetics at The Institute of Cancer Research, London, said: "We are starting to complete the picture of how CLL development is dictated by mutations in regions of the genome connected to specific aspects of DNA repair. These genetic factors explain a significant proportion of inherited cases of CLL."
The total number of risk variants for CLL identified is now 30, with the genetic factors newly identified by the study found around a set of genes responsible for the function of telomeres. Telomeres are sections of DNA that cap the end of chromosomes, preventing damage during cell division and the creation of mutated and eventually cancerous cells.
Professor Chris Bunce, Research Director at Leukaemia & Lymphoma Research, said: "These findings are very important - the identification of this cluster of so many risk variants around these neighbouring genes greatly deepens our understanding of how CLL develops. The challenge is now to use this information to improve treatments for this blood cancer, which remains incurable."