MKI67 and neuroendocrine neoplasm: NENs are classified into well‐differentiated neuroendocrine tumors (NETs) and poorly differentiated neuroendocrine carcinomas (NECs); NETs are further subclassified into NET G1 (Ki67 index < 3% and/or mitotic count < 2/2 mm2), NET G2 (Ki67 index: 3–20% and/or mitotic count: 2–20/2 mm2), and NET G3 (Ki67 index >20% and/or mitotic count >20/2 mm2).17