Tumor markers have biological functions that we should know. CEACAM1 as an example

Tumor markers are substances widely used in the daily practice and its main clinical application generally lies, not in the diagnosis but in the patient’s follow-up, because they are useful for early detection of a relapse/metastasis and to know the effectiveness of an established therapy. These markers have a main indication in daily practice, but almost all lack specificity because they can be elevated in different tumors. There are a number of aspects of tumor markers that we must know if we want to well understand them in regular practice: metabolism, half-life, hormonal dependence, temporary elevations by known or unknown causes, dosage moment, etc., all of which makes a tumor marker not just as a single biochemical parameter [1]. In that regard, we should recall that tumor markers have normal biological functions that often go unnoticed. With this in mind, we summarize in this editorial normal role of tumor markers (excluding any link with malignant proliferative function), using as example CEACAM1.