Manipulating genes to treat pituitary tumours

Professor Bill Farrell has identified that some genes have been turned off. Turning them back on might stop a pituitary tumour growing.

Research into ‘epigenetics’ has discovered that some cancers arise because a gene that controls an important process has been ‘silenced’ from outside, in a process called methylation.

Professor Bill Farrell from the University of Keele explains: ‘This mechanism is effectively throwing a blanket over the gene. If the silenced gene is supposed to be telling other cells not to divide, they just carry on multiplying and a tumour is born. ‘The really exciting thing about genes that have been silenced is that it should be possible to reverse the methylation process and switch them back on,’ says Bill.

But which genes have been silenced and which need to be switched on? With PhD student Kevin Dudley, Bill examined laboratory tumours that grow in culture. ‘Initially, we found 68 genes that were switched off in these pituitary tumours,’ explains Bill. He’s particularly interested in tumours in the pituitary gland in the brain because ‘Pituitary tumours account for between 10% and 15% of all brain cancers and about one third invade other parts of the brain and, despite surgical removal, recur. So I’m looking for epigenetic errors that trigger this process.’

Bill then examined five of these genes in a retrospective study of pituitary cancers in people and showed that the laboratory model was successful in predicting what happens in humans.

What does this mean for brain tumour patients? Bill hopes that it will be possible to classify brain tumours by their genetic make-up. This will allow surgeons to take samples and determine how dangerous – or not – the tumour is. Switching the silenced genes back on might stop cancer cells spreading into other parts of the brain or make dangerous cells more vulnerable to drug treatments.