GEP-NETs are well-differentiated neoplasms, defined as grade G1 (Ki-67 < 3%, mitotic count < 2/2 mm2), G2 (Ki-67 3–20%, mitotic count 2–20/2 mm2), or G3 (Ki-67 > 20%, mitotic count > 20/2 mm2). The gene discussed is MKI67; the disease is neoplasm.