[Tumor markers in prostate cancer].

The present status of tumor markers in prostate cancer, especially prostate-specific antigen (PSA), for diagnosis and follow-up of prostate cancer patients was reviewed. Due to tissue-specific protein of PSA as well as PAP, serum PSA levels may increase in patients with benign hyperplasia (BPH) which is the disease necessary for differential diagnosis from prostate cancer. Therefore, it has been believed to be difficult to differentiate early stages of prostate cancer from BPH using only PSA determination. However, with the use of recently developed assay systems, the detection of PSA-protease inhibitor complex, or PSA-density, the detection of early stages of prostate cancer may be possible. In following up prostate cancer patients, serially determined PSA is one of the best tools to evaluate treatment response and early detection of disease progression.