In a study of men with prostate cancer classified either as indolent or lethal based on their survival over a 10-year follow-up period, the presence of each additional CD4+ Treg cell was associated with a 12% increase in the odds of lethal prostate cancer, independent of other clinical factors, such as the tumor stage, tumor volume, and Gleason score [63]. The gene discussed is CD4; the disease is prostate cancer.