Pitfalls in Tumor Markers Testing

Tumor markers are molecules that are produced by cancer cells or by other cells of the body in response to cancer or certain benign (noncancerous) conditions. More than 20 different tumor markers have been characterized and are in clinical use. Tumor markers can be used for various purposes, including screening a healthy population or a high-risk population for the presence of cancer; making a diagnosis of cancer or of a specific type of cancer; determining the prognosis in a patient; predicting in advance the likely response to therapy; and monitoring the course in a patient in remission or while receiving surgery, radiation, or chemotherapy. This chapter discusses most commonly used tumor markers, difficulty in interpretations, limitations, and the interferences in the laboratory results. The hook effect and interferences of heterophile antibodies in tumor marker assays are also discussed in detail.