New genes linked to brain and ovarian cancer

New genes indicating risk of ovarian and brain cancer have been identified using genome-wide association studies (GWAS).

Using data from tens of thousands of individuals, two separate studies have identified 12 new gene variants linked to ovarian cancer and 13 new variants linked to glioma, a form of aggressive brain cancer.

'It's been exciting to have been involved in such a gigantic study including cases of brain cancer from all over the world,' said Richard Houlston, professor of molecular and population genetics at the Institute of Cancer Research (ICR), London, and co-leader of the glioma study. 'We've uncovered a treasure trove of new information about the genetic causes of glioma brain cancers.'

'If we can understand how [the genes] work, we will be in a better position to treat — and possibly prevent — ovarian cancer,' said Dr Simon Gayther of Cedars-Sinai Medical Center, Los Angeles, a co-author of the ovarian cancer study.

The glioma study was carried out by a team of scientists from 14 cancer centres in the UK, Europe and the US, who looked for inherited DNA changes that increased the risk of the disease. They performed two GWAS and combined the results with six previous studies, involving data from a total of over 30,000 people with and without glioma.

The researchers identified 13 new genetic changes associated with different cell functions which increased the risk of glioma. They also found different sets of genes were responsible for developing the two subtypes of glioma, indicating different approaches to treatment may be more effective.

As a result of the study, there are now 26 known gene variants associated with risk of glioma.

'The genetics of glioma had been poorly understood, but this huge and excellent new study at a stroke gives us the same kind of knowledge of the disease as we have with other, more intensely studied cancers,' said Professor Paul Workman of the ICR, who was not involved in the study.

The ovarian cancer study was carried out by the OncoArray Consortium, a team of 418 scientists from the UK, the US and Australia. They performed a GWAS of almost 100,000 people, including 17,000 patients with the most common form of ovarian cancer.

'We know that a woman's genetic make-up accounts for about one third of her risk of developing ovarian cancer. This is the inherited component of disease risk,' explained Professor Paul Pharoah from the University of Cambridge, UK, one of the joint leads.

The researchers identified 12 new genetic variants associated with risk of ovarian cancer, and confirmed 18 variants previously published elsewhere.

There are now 30 known variants associated with ovarian cancer, accounting for 6.5 percent of inherited risk. However, some variants are common and women carrying the greatest number of variants will have a lifetime risk of just 2.8 percent. Ovary removal is usually offered to women with a risk of 10 percent or more.

'In some ways, the hard work starts now,' said Dr Gayther. 'We really have little idea of the functional effect these variants have at the molecular or cellular level and so there are few clues as to how they might affect risk. If we can understand how they work, we will be in a better position to treat – and possibly prevent – ovarian cancer.'