CORRECTION APPENDEDA common sexually transmitted disease thought to have virtually no visible symptoms in men may actually be putting men at risk for advanced prostate cancer, according to a Harvard study released earlier this month. Researchers followed two groups of men suffering from prostate cancer—one with the sexually transmitted infection Trichomoniasis, caused by a parasite—and found that the group suffering from the infection developed more likely to suffer from more severe forms of cancer. According to the study, at least 174 million people worldwide suffer from Trichomoniasis. And though the disease is treatable with antibiotics, its relatively silent nature in males complicates efforts at treatment. Because Trichomoniasis usually affects women, men are often unaware of their condition. Many men only realize that they have the infection when their female partner is diagnosed—a troubling prospect if the link with severity of prostate cancer proves causal. “Prostate cancer is the most common cause of cancer among men in westernized countries,” said Jennifer Stark, the study’s lead author and a 2008 graduate from the School of Public Health. “It’s also the second leading cause of cancer-related death; it’s a big public health problem.” Although most men with prostate cancer have good outcomes, Stark stressed that the link they found for Trichomoniasis was with particularly advanced forms of prostate cancer, making the finding of potentially high importance for efforts to combat prostate cancer deaths. “What we really want to do is find how we can prevent aggressive prostate cancer from happening,” said Lorelei A. Mucci, a School of Public Health assistant professor and the study’s senior author. The study built on research released last year that suggested a link between the infection and prostate cancer, but the new study included more subjects with advanced forms of cancer. There had only been two other studies on Trichomonas Vaginalis, the parasite that causes the infection, and neither had had enough advanced-state prostate cancer cases or long-term follow up to draw conclusions from mortality rates, Mucci said. Further research will be necessary before researchers can conclude that there is a cause-and-effect relationship between the two conditions. “We have not shown that Trichomonas Vaginalis causes prostate cancer at all,” Stark said. “In order to make that giant leap from our study to something that would demonstrate causation...we need to show that being infected with TV leads to changes in the prostate,” she added.CORRECTIONAn earlier version of the Sept. 25 news article "STD Linked to Prostate Cancer" misspelled the last name of the lead author of the study. Her name is Jennifer Stark, not Jennifer Star.For recent research, faculty profiles, and a look at the issues facing Harvard scientists, check out The Crimson's science page.