Laboratory medicine plays an increasingly important role in the management of cancer patients (1, 2) . In none of the tumors has the advent of biomarkers changed the treatment in a more fundamental way than the introduction of prostate specifi c antigen (PSA) which has virtually transformed the management of prostate cancer. Prostate cancer represents a major public health problem. The last decade has witnessed a hitherto unprecedented progress in the treatment of pro state cancer, including surgical therapy, radiation therapy or systemic treatment. In the case of prostate cancer, laboratory medicine has contributed not only to an early diagnosis, but had an equally important impact on the management of the tumor during the entire course of the disease. In fact, the introduction of PSA has likely changed the course of the treatment of this tumor to the extent that we now distinguish between the ‘ pre-PSA era ’ and the ‘ PSA era ’ . The assessment of the disease course and the effect of therapy in patients with prostate cancer are currently based largely on serial PSA measurements. In patients after the radical therapy of the primary tumor, detection of a sustained rise of PSA is the basis for the diagnosis of relapse, termed biochemical relapse, and leads to the institution of therapy even if there is no evidence of a tumor on the imaging studies.