Abstract
A tumor marker is a substance presents in the tumor or produced directly by the tumor or by non-tumor cells as a response to the presence of a tumor and may be found in the blood, urine or body tissues. An elevated level of a tumor marker can indicate cancer; however, there can also be other causes of the elevation.
Contemporary research is focused predominantly on new tumor markers and evaluation of their diagnostic, prognostic and predictive significance for routine clinical practice. Molecular tumor markers very well reflect pathobiological processes in tumors.
This article is intended to encourage more appropriate use of tumor marker tests by primary care physicians, hospital physicians, and surgeons, specialist oncologists, and other health professionals.