There are a number of tumor markers available today enabling the early detection of malignancies thus saving the life of many thousands of people worldwide. By definition, tumor markers are substances in tissues, blood, bone marrow or other body fluids that appear in cancer patients' samples or are present at significantly elevated levels compared to normal conditions. The first marker of malignant disease in modern medicine was identified in 1846 by the English physician-chemist Henry Bence-Jones. Yet, that time, of course, he was not aware that the protein (named as Bence-Jones) he dicovered, was a pathogenic indicator of multiple myeloma. The classic era of tumor markers started in the 1960s by discovery of two leading oncofetal antigens, alpha-fetoprotein (AFP) and carcinoembryonic antigen (CEA). AFP was published 1944 by Swedish scientist Kai O. Pedersen, while the discovery of CEA is associated with two Canadian physicians, Phil Gold and Samuel O. Freedman. One of the most widely known tumor markers indicating prostate cancer is the prostate-specific antigen, or PSA. The discovery of PSA as a clinically useful marker of prostate cancer and its translation into clinical practice can be attributed to Ming C. Wang, who described the molecule in 1979. The US Food and Drug Administration (FDA) approved PSA in 1986 as a molecule for monitoring the disease, and 1994 it licenced the measuring of PSA levels as a screening test, thus facilitating the early detection of prostate cancer and enabling more effective treatment.  Kulcsszavak: tumormarker-kutatás, alfa-fötoprotein (AFP), carcinoembryonalis antigén, prosztata specifikus antigén (PSA)