High-grade (G3) neuroendocrine neoplasms (NENs) account for about 10–20% of malignant extrapulmonary neuroendocrine neoplasms,1 and are characterised by a Ki-67 proliferative index >20% and/or mitotic index >20/10 high powered fields (HPF). The gene discussed is MKI67; the disease is neuroendocrine neoplasm.