Genetics of common brain cancer revealed by two studies

Nearly all cases of meningioma - the commonest kind of brain tumour - can be traced back to a fault in one of just five genes, scientists say.

Around half of all meningioma tumours were already known to be linked to a mutation or deletion of a gene called neurofibromin 2, or NF2. When a team at Yale University School of Medicine in the USA analysed the genomes of 300 meningiomas they identified four other genetic mutations they say explain the non-NF2 cases.

Each of these mutations was linked to the growth of tumours in distinct regions of the brain and the likelihood of a tumour becoming malignant.

Accordingly, senior author Murat Günel, professor of neurosurgery, genetics and neurobiology at Yale said that the study has 'direct clinical relevance and opens the door for personalised therapies'.

One of the mutations identified in the study, on the SMO gene, is already linked to basal cell carcinoma, a form of skin cancer, and a drug acting on the SMO gene product is approved as treatment for that disease.

Currently, treatment for meningioma is limited to surgery. Although 90 percent of meningioma tumours are benign they often still require surgery as continued growth can impact brain function and even be life-threatening.

A second, unrelated, study on the genetics of meningioma appeared in Nature Genetics, focusing on two of the mutations identified in the Science paper. Genetic analysis of 65 tumours showed that mutations in the SMO and AKT1 genes occured in a minority of cases.

'The wonderful thing about those mutations is that there are already drugs in the clinic to target cancers with those mutations', said study leader Dr Rameen Beroukhim, from the Dana-Farber and Broad  institutes in Boston, USA.

Talking to Bloomberg News, Dr Beroukhim said that 'the hope is that patients with the mutations may respond to these drugs'. However, Bloomberg's article goes on to note that no clinical trials to test the drugs in meningioma have been scheduled.