Nerves in the endometriosis lesion release chemicals like colony-stimulating factor-1 (CSF-1), chemokine ligand 2 (CCL-2), leukemia inhibitory factor (LIF), and pancreatitis-associated protein III (PAP-III), which induce the migration of macrophages toward the nerve ending [18,30,35,36]. Here, LIF is linked to endometriosis.