Biomarkers are measurable indicators, frequently a molecule, that indicate health or a pathologic state, pharmacological responses, etc. They are used in many fields of science and health care. For a long time, biomarkers were only identifiable in the serum because they are in higher quantities in the bloodstream than in other fluids such as saliva or urine.
Technology has now advanced to the point where minute quantities of the same biomarkers are detectable in saliva. Some of these salivary biomarkers are in nanogram or picogram quantities. A nanogram is a billionth of a gram; a picogram is a trillionth of a gram—both astronomically small quantities.
This does not answer the question of where they come from, just where they are detected. If there is a malignant lesion somewhere in the body, that lesion throws off small bits of itself, almost like a clue providing evidence of the lesion’s existence. The small bits of evidence are the biomarkers.
How do they get into the salivary glands to be subsequently secreted into the oral cavity? The biomarkers are transported by the lymphatic system and the bloodstream. The exact mechanism by which they get in the salivary glands, and which ones, is not known with complete certainty at this point.
There is a ton of research going on around the world looking at salivary biomarkers for identification of wide-ranging purposes. One of the things we will see in the foreseeable future is chairside salivary identification of periodontal pathogens and cariogenic bacteria. This was the stuff of science fiction only a short time ago. Going forward we will see more requests for a salivary sample than a blood draw or urine sample. It’s good to be in the dental profession at this time!