Indeed, ROS producing enzymes such as myeloperoxidase (MPO) and nicotinamide adenine dinucleotide phosphate (NADPH) oxidase subunits have been found upregulated in microglia within and in the proximity of MS lesions, both in WM and GM (Nagra et al., 1997; Gray et al., 2008a,b; Fischer et al., 2012). The gene discussed is MPO; the disease is myeloid sarcoma.