Immunochemical staining revealed that Ki-67 was 40% positive, and the cells were positive for myeloperoxidase (MPO), lysozyme, and Naphthol AS-D chloroacetate esterase (NASDCA)Giemsa staining, leading to a diagnosis of ileal MS (Fig. 3e–h). The gene discussed is MPO; the disease is myeloid sarcoma.