New genomics research has found that a simple blood test can determine which men are likely to develop prostate cancer. Researchers at found that five genetic variants previously associated with prostate cancer risk have a strong cumulative effect. Researchers found that a man with four of the five variants has an increased risk of 400 to 500 percent compared to men with none of the variants. The researchers then added a family history of prostate cancer to the equation — for a total of six risk factors. A man with at least five of the six factors had increased risk of more than 900 percent.