Study identifies first gene links to most common brain cancer

6 July 2009

The first genetic variants that increase the risk of developing glioma, the most common form of brain tumour, have been identified by scientists part-funded by the Wellcome Trust.

After studying the genomes of over 4000 people with cancer, five common gene variants have been identified by a team of researchers from the UK's Institute of Cancer Research, the USA's University of Texas MD Anderson Cancer Center and colleagues.

According to the study published in the journal 'Nature Genetics', the more of these variants are present, the higher the risk of developing glioma.

"We've found the first real evidence that variations in the genes which many people carry can increase their risk of this deadly disease," said Professor Richard Houlston from the Institute of Cancer Research, lead researcher on the study.

People who have a relative diagnosed with brain cancer are twice as likely to develop the disease themselves. Recent genetic research has revealed that most cancers are triggered not by one or two genetic mutations but through many genetic factors, each raising the risk of cancer slightly.

In the new study, the researchers compared the DNA of over 1800 people with glioma with healthy people from the UK and USA, and confirmed their results by studying a further 2545 cases and nearly 3000 healthy people from across Europe.

They found that the risk of developing glioma increases the more of the five gene variants a person carries - humans carry two copies of each gene, so a person may have up to ten of the five glioma variants in their genome. The study revealed that those with eight or more of these are three times more likely to develop glioma than the general population.

The researchers believe the new variants account for 7-14 per cent of the inherited risk of glioma cancer, and hope further research will identify more variants.

The study also sheds new light on how glioma develops, which may form new biological targets for treatments. Some of the genetic regions found were associated with genes previously linked to cancer development.

Glioma accounts for about 80 per cent of primary malignant brain tumours (cancer that starts in the brain and has not spread from elsewhere); about 4550 people are diagnosed with brain tumours in the UK each year.

Image: Brains in a beaker - four different manipulations of a photograph taken of a human brain. Credit: Heidi Cartwright, Wellcome Images

References

Shete et al. Genome-wide association study identifies five susceptibility loci for glioma. Nat Genet 2009 [Epub ahead of print].