The translocator protein (TSPO), an 18 kDa protein with five transmembrane domains primarily localized in the outer membrane of mitochondria, is overexpressed in activated macrophages and can serve as an attractive surrogate marker for Alzheimer’s disease, multiple sclerosis, Huntington’s disease, various cancers, ischemic brain injury, myocarditis, DLI and rheumatoid arthritis [7,8,9,10,11,12,13,14,15,16]. The gene discussed is TSPO; the disease is Alzheimer disease.