[PSA-based parameters].

Serum prostate-specific antigen (PSA) is used for the screening and early detection of prostate cancer. We are, however, confronted with the dilemma that a significant number of unnecessary biopsies are unavoidable especially in the serum PSA range of 4 to 10ng/ ml. It has been reported that age-specific PSA reference ranges, PSA velocity, PSA molecular forms and volume-adjusted PSA are valuable tools to improve specificity for early diagnosis of prostate cancer. In recent years, free PSA has been demonstrated to be composed of several isoforms including pPSA, BPSA and so on. Clinical values of these new PSA isoforms as well as human glandular kallikrein 2 are anticipated to be fully investigated to reduce unnecessary biopsies without missing a significant number of prostate cancer in the near future.