MKI67 and neoplasm: In 2004 the Ki‐67 index became a crucial prognostic factor for the classification of pancreatic neuroendocrine neoplasms (PanNENs) and has been demonstrated in the protocols and guidelines applied by the North American Neuroendocrine Tumor Society [87], American Joint Committee on Cancer (AJCC) [88] and European Neuroendocrine Tumor Society [89].