In the anti-coagulated plasma collected at baseline, median levels of total PSA, complexed PSA, free PSA and hK2 were higher, and median free-to-total PSA ratio lower, for men who were found to have skeletal metastases or clinical stage at least T3 at the time of prostate cancer diagnosis, compared with men not diagnosed with prostate cancer. The gene discussed is HK2; the disease is prostate cancer.