TNF-alpha (tumor necrosis factor alpha), IL-1, IL-2, IL-4, IL-6, epidermal growth factor (EGF), converting growth factor alpha (TGF-alpha), TGF-1, and TGF-2 have been recognized at elevated levels in nigrostriatal areas of the CNS and ventricular cerebrospinal fluid of Parkinson’s disease patients, supposedly emerging from activated microglia [37,39,40]. Here, EGF is linked to Parkinson disease.