In the pathological brain, OPN is implicated as a mediator of pro-inflammatory effects in a variety of neurodegenerative diseases such as multiple sclerosis (Kim et al., 2004; Hur et al., 2007; Niino and Kikuchi, 2011), Alzheimer’s disease (Wung et al., 2007; Comi et al., 2010; Wirths et al., 2010), Parkinson’s disease (Iczkiewicz et al., 2006; Mattson et al., 2008), and ischemic stroke (Ellison et al., 1998; Wang et al., 1998; Schroeter et al., 2006; Choi et al., 2007). The gene discussed is SPP1; the disease is Alzheimer disease.