Obesity is associated with a worse prostate cancer prognosis among men whose tumors contain a specific genetic mutation, suggest results from a new study led by Harvard School of Public Health, Dana-Farber Cancer Institute, and Brigham and Women’s Hospital researchers. Among prostate cancer patients whose tumors contain the mutation, they had a more than 50 percent increased risk of dying from prostate cancer if they were overweight or obese compared to healthy-weight men; among men whose tumors did not have the mutation, there was no effect of obesity on cancer survival. It is the first study to link data on obesity, tumor genetics, and cancer-specific survival in prostate cancer patients.