KLK3 and sexually transmitted disease: In following up a brief report from 2001 linking raised PSA to high titres of anti-chlamydial antibody in young gold miners attending a STD clinic in South Africa [9], Sutcliffe and colleagues from the Johns Hopkins group, in a series of reports starting in 2006 [62,63], found statistical significance between a history of three types of sexually transmitted infection (chlamydia, gonorrhoea, and non-chlamydia, non-gonorrhoea urethritis) and a raised PSA, which persisted when followed up, up to 10 years after initial screening [63].