Search for more breast cancer genes underway

Up to a third of all cases of breast cancer could have a genetic basis, a leading UK scientist said last week. Speaking at the annual conference of the National Cancer Research Institute, Professor Bruce Ponder said that research suggests there could be hundreds of variations in dozens of genes, which could each raise a person's cancer risk by a tiny percentage. Ponder is leading a £1.7 million project to identify these genes at Cancer Research UK's laboratories in Cambridge.

Most cases of breast cancer are not inherited, but around 5-10 per cent are due to a mutation in genes such as BRCA1 or BRCA2. Whilst most women have a 13 per cent chance of developing the disease in their lifetime, those with BRCA1 or BRCA2 mutations can face up to an 85 per cent chance. However, researchers have long suspected that there are many other gene variants, which - although they are not linked to clearly inherited forms of breast cancer - can increase a person's risk of the disease. For example, last year, researchers from St George's Hospital in London found that particular variations in the vitamin D receptor (VDR) gene can nearly double the risk of developing breast cancer.

The Cambridge researchers are comparing genetic differences between healthy and cancerous cells, to identify those that are linked to an increased inherited risk of the disease. Ponder said that so far, scientists had been studying genes involved in cell growth, with limited success. 'We've looked at over a hundred such potential candidates but, in total, they explain no more than a few per cent of the familial risk', he said. But using new technology, he expects that the pace of research will now speed up 'vastly', since 'it allows us to trawl through thousands of genes in a single experiment, rather than test one gene at a time'. The Cambridge team hopes that its research will eventually lead to more accurate identification of people who have a higher chance of developing breast cancer, paving the way for personalised treatment.

Mrs Gillian Gatley, from Rochford in Essex, is one of those participating in the research. Her sister and cousin died from breast cancer, and her father and brother died after developing pancreatic cancer. Mrs Gatley and another sister Theresa Holman have both had double mastectomies to reduce their risk of breast cancer. 'When I heard about the research I thought of my children', she told the Daily Telegraph newspaper, adding 'it raises the possibility of embryo screening. I would not want my children to go through what we have all been through, even though I think I got off lightly'.