Sexually transmitted infections of the parasite Trichomonas vaginalis in men can lead to colonization of T. vaginalis in the prostate, which correlates with risk of developing aggressive prostate cancer. Twu et al. found that T. vaginalis macrophage migration inhibitory factor (Tv-MIF), which is secreted by the parasite, has pro-inflammatory activity, like the human homologue. Tv-MIF also binds to the human MIF receptor, which resulted in activation of downstream signalling, including ERK and AKT phosphorylation. Furthermore, they showed that Tv-MIF increases the growth and invasion of prostate cancer cells and of benign prostate cells in vitro. This indicates that Tv-MIF from chronic T. vaginalis infections may drive prostate inflammation, which could lead to tumorigenesis.