The chemokine C-C motif ligand 2 (CCL2), also referred to as monocyte chemoattractant protein 1, is released from injured neurons and activates the C-C chemokine receptor type 2 (CCR2) in macrophages, which induces macrophage activation and proliferation in the dorsal root ganglion (DRG) following peripheral nerve injury [8, 24]. The gene discussed is CCL2; the disease is peripheral nerve injury.