While carcinomas are invariably aggressive diseases (8–10), NETs are usually slow-growing neoplasms (11) that the latest WHO classification (12) categorized into 3 subtypes based on the proliferative index (e.g., mitotic counts or percentage of Ki67 positive cells): NET G1 (Ki67 index <3%), NET G2 (3%-20%), and NET G3 (>20%). The gene discussed is MKI67; the disease is neoplasm.