Although genetic tests of tumors are already used to determine whether certain drugs will work for several types of cancer, this is the first time researchers have found such a test for prostate cancer, de Bono’s group says. Olaparib could offer a new option for these men: The trial shows “this is a good swat at that disease,” said prostate cancer researcher William Nelson of Johns Hopkins University in Baltimore, Maryland, at an AACR press conference, adding that the prospect of genetic testing to identify prostate cancer patients who could benefit from olaparib “looks very promising.”