The use of the Ki-67 index and/or mitosis in the WHO and ENETS grading systems was validated for foregut and pancreatic NENs (PanNENs) by several studies and their biological relevance and power to discriminate among prognostic groups has mostly been confirmed.19–23 However, to the best of our knowledge, no previous report of the prognostic validation of gastric NETs according to both grading systems has been published. The gene discussed is MKI67; the disease is pancreatic neuroendocrine neoplasm.