Cancer Detection: DNA Study Brings 'New Era'

Scientists have revealed a major leap forward in cancer detection after finding dozens of common genetic changes that can increase the risk of the disease.

Tests on 250,000 patients found 83 inherited variations in the DNA code that could either raise or lower the chances of developing breast, ovarian or prostate cancer.

Together the cancers affect almost 100,000 people a year in the UK. More than 26,000 of them die.

The findings will allow doctors to identify women with a near 100% chance of developing breast cancer, and men with a one in two risk of prostate cancer.

Scientists have hailed the research as the dawn of a new era in cancer diagnosis and treatment.

Professor Ros Eeles from The Institute of Cancer Research said: "These results are the single biggest leap forward in finding the genetic causes of prostate cancer yet made.

"They allow us, for the first time, to identify men who have a very high risk of developing prostate cancer during their lifetime through inheritance of genetic variants.

"If we can show from further studies that such men benefit from regular screening we could have a big impact on the number of men dying from the disease."

This is the largest study of its kind, involving around 1,000 scientists around the world. They analysed DNA for tiny changes that could change the way genes work, altering cancer risk as a result.

In the near future patients could be asked to spit into a tube by their GP who could then run a £30 test on their DNA in the surgery.

They would then have an individual risk profile for some of the most common cancers.

The most immediate practical use of the research could be in women who carry the inherited breast cancer gene BRCA1. On average they face a 70% risk of developing breast cancer in their lifetime.

But the new genetic variants can give women much more detail on their risk. If they also inherit several of the newly identified high risk changes to their DNA their chances of developing the disease are raised to between 90 and 100%.

But if they inherit the protective DNA changes, their risk drops to below 30%.

Scientists say it could help women with the BRCA gene decide whether to have a preventative mastectomy. Sharon Osborne had her breasts removed last year because she carried the gene.

Professor Montse Garcia-Closas, another of the researchers, said the study was a "huge step" in understanding the causes of breast cancer.

"These findings will help us to predict who is at increased risk of developing the disease and who could benefit most from prevention strategies, such as lifestyle changes and chemo-prevention, and early-detection strategies, such as regular screening," she said.

Around 57% of cancer risk is set by genetic factors, with lifestyle making up the rest.

Scientists believe there could be thousands of genetic variations that affect cancer risk. Patients with lung and colorectal cancers are to be tested as part of a study starting this summer

The study was funded by Cancer Research UK and the Wellcome Trust. The results are published in a series of papers in journals including Nature Genetics, PLOS Genetics, and the American Journal of Human Genetics.