NGF and melanoma: There are greater levels of mitogenic cytokines and growth factors in melanoma compared to benign melanocytic nevi, including CXCL1, CXCL2, IL-6, IL-8, oncostatin M (OSM), nerve growth factor (NGF), granulocyte-macrophage colony-stimulating factor (GM-CSF), VEGF-A and platelet derived growth factor β (PDGF-subunit β) [16].