The best example of a validated biomarker in craniofacial pain is CGRP in migraine, the levels of which are elevated in blood and saliva during migraine attacks.80 The prospective utility of these signaling molecules as biomarkers is further enhanced by the availability of targeted pharmacological therapies that are already in clinical use, including 5-HT modulators, norepinephrine reuptake inhibitors, α2 agonists, and CGRP receptor antagonists. Here, HTR5A is linked to migraine disorder.