MKI67 and digestive system neoplasm: According to the revised WHO classification in 2010, pancreatic and gastrointestinal tumors with endocrine properties are collectively called neuroendocrine neoplasms and can be divided into 3 major categories, Grades 1 and 2 neuroendocrine tumors (NETs) and neuroendocrine carcinomas (NECs), depending on their degree of proliferation and malignant potential, measured using the Ki-67 labeling index [6], with NECs having a Ki-67 labeling index >20%.