Guida all'uso clinico dei biomarcatori in oncologia: premesse e generalità

In this document a working definition of circulating cancer biomarkers is provided and discussed within a broader definition of disease biomarkers and their possible classifications. The biomarker families possibly suitable for clinical use on the basis of available evidence are then considered, concluding that only few biomarkers may be helpful in the management of cancer patients. They are well known molecules discovered 20-30 yeas ago, quantitatively related to the tumour burden, encompassing classical "tumor markers" (CEA, AFP, hCG) and glycoproteins discovered by immunologic recognition (CA 125, CA 15.3, CA 19.9). The most relevant characteristics of quoted biomarkers are reported. The poor "cancer specificity" of available biomarkers is discussed, concluding that circulating concentrations of the socalled "tumor" markers are the sum of several variables including (if present) the malignancy. Non-tumor variables potentially responsible of variations in circulating concentrations of biomarkers are reported. They include physiological conditions and life style patterns, diseases other than cancer, and iatrogenic artefacts. The analytical and pre-analytical issues that may interfere with the biomarker determination, including autoantibodies, human antimouse monoclonal antibodies, and the "hook effect", are also examined.