Scientists find genes that affect risk of common brain tumour
Scientists from the UK have helped to identify a number of genetic variants that appear to increase a person's risk of developing glioma, the most common type of brain tumour.
Although the causes of gliomas are largely unknown, scientists have long suspected that an individual's genes affect their risk, as people with a family history of the disease are twice as likely to be diagnosed with the condition themselves.
An international team involving scientists from the UK's Institute of Cancer Research (ICR), the University of Texas MD Anderson Cancer Centre in the US and other centres in Europe worked together to study the DNA sequences of thousands of people.
They have identified five genetic factors that are more common in people with gliomas, which account for around four fifths of primary malignant brain tumours and affect around 4,550 people in the UK each year.
Lead researcher Professor Richard Houlston, who is part-funded by Cancer Research UK and is based at the ICR, described the findings in the journal Nature Genetics as a "major discovery".
"We've found the first real evidence that variations in the genes which many people carry can increase their risk of this deadly disease," he said.
The researchers studied the DNA of 1,878 glioma patients and a further 3,670 cancer-free individuals.
They found 'variant' versions of five genes that are more common in people with glioma, which they then confirmed by studying the DNA sequences of a further 2,545 glioma patients and 2,953 cancer-free people from Europe.
The more variants a person has, the greater their risk of developing glioma.
People with eight or more copies of the variants - out of a possible ten copies (five of each from their mother and father) - are three times more likely to develop glioma compared with the general population.
The researchers believe that there are still more genetic factors to be found and that the five identified in their study probably account for between seven and 14 per cent of the inherited risk of glioma.
Professor Peter Rigby, chief executive of the ICR, said: "These findings have important implications as glioma is one of the most common tumours in middle-aged people, and the prognosis for sufferers is poor.
"We would also hope that this research could ultimately help scientists develop new treatments that are targeted at patients' specific molecular defects."
Dr Lesley Walker, director of cancer information at Cancer Research UK, noted that little is known about the lifestyle or genetic factors that affect a person's risk of developing a brain tumour.
"This large new study is an important step forward as it unlocks some of the first genetic secrets behind the most common type of brain tumour, glioma," she said.
"Identifying these genetic variants will open up new avenues for scientists to explore, helping them to better understand how gliomas develop, identify who might be most at risk and ultimately find improved ways to diagnose and treat the disease."