They can be distinguished into well‐differentiated neuroendocrine tumors (NETs), poorly differentiated neuroendocrine carcinomas (NECs) and mixed neuroendocrine‐non‐neuroendocrine neoplasms (MiNENs) based on morphology and markers of proliferation such as Ki‐67 index and/or mitotic rate.4, 5. This evidence concerns the gene MKI67 and neuroendocrine neoplasm.