NGF and cutaneous mastocytosis: In contrast, a study by Jang et al. on patients with CM and controls revealed that levels of NGF and other neuropeptides such as CGRP and substance P showed elevations in persons with migraine disease, a positive correlation was noted between NGF and these other neuropeptides, and levels of NGF and the aforementioned neuropeptides significantly correlated with intensity of pain [37].