Is Prostate Cancer an STD? Researchers link it to infection By Matt Cantor, Newser User Posted May 20, 2014 7:34 AM CDT 3 comments Comments Researchers have linked a sexually-transmitted infection to prostate cancer. (Shutterstock) (Newser) – Prostate cancer may be tied to an infection transmitted during sex, researchers report. They call for more investigation into the possibility that the cancer could be associated with trichomoniasis, the world's most common non-viral sexually transmitted infection. Trichomoniasis affects some 275 million people, the BBC reports, and many have no symptoms. The latest study follows on previous research, including a 2009 study that found a quarter of men suffering from prostate cancer also had trichomoniasis. The new research finds that the parasite behind the infection gives off a protein that can fuel cancer's growth. But "previous evidence in patients failed to show a clear link between prostate cancer and this common sexually transmitted infection," notes an outside expert, who adds that there remains "no convincing evidence for a link with infection," the Independent notes.