Seven new genetic variants have been found that contribute to a 25 per cent increased risk of inherited prostate cancer.
They have been added to a list of more than 33 previously known risk-increasing mutations.
Men who possess most of the variants have a 50/50 chance of developing the disease, but only about one per cent of males are believed to fall into this category.
Prof Ros Eeles, from the Institute of Cancer Research in London, who led the research, said: “We do not yet know whether this is a type of prostate cancer that needs earlier treatment and we are doing further work to determine this.
“These results bring nearer the day when we can use genetics to tailor our screening and treatment of men at risk of this disease.”
Each year around 35,000 men are diagnosed with prostate cancer and 10,000 die from the disease. Like other cancers, prostate cancer is caused by a combination of environmental and genetic factors.
The scientists, whose findings are published in the journal Nature Genetics, analysed the DNA of more than 4,500 cancer patients and a similar number of healthy individuals.