Molecular forms of prostate-specific antigens and human kallikrein 2 as possible indicators in prostate cancer diagnostics

Prostate-specific antigen (PSA) is the most useful marker in the early dete ction of prostate cancer and in the monitoring of patients with this diagno sis. Molecular forms of PSA and human kallikrein 2 (hK2) have been used to discriminate between benign prostatic hyperplasia and prostate cancer,as we ll as for the detection of prostate cancer within the gray zone of PSA. In this respect,a literature survey on the diagnostic validity of free PSA (fPSA) related to total PSA (tPSA), PSA bound to alpha(1)-anti-chymotrypsin (ACT-PSA), and complexed PSA (cPSA) is given together with our own results . The ratio of fPSA/tPSA has been sh own to improve both sensitivity and spec ificity of prostate cancer diagnosis based on tPSA measurements. The number of biopsies can be reduced in the total PSA range of 4-10 mu g/l. Furtherm ore,carcinomas can be detected in patients with PSA values less than 4 mu g /l.ACT-PSA or cPSA alone and the calculated derivatives are not superior in their discriminatory power compared with tPSA and the fPSA% value. The oth er molecular PSA forms and hK2 are still objects of research and their diag nostic significance needs to be evaluated in more extensive clinical trials .