However, along with IVD degeneration, IVD ruptures, especially AF fissures, promote the ingrowth of sensory nerve fibers immunohistochemically labeled with the protein gene product 9.5 (PGP 9.5), (calcitonin gene-related peptide) CGRP, neurofilament, or substance P toward the inner AF and NP lesions [35,36,37,38]. The gene discussed is TAC1; the disease is atrial fibrillation.