MKI67 and pancreatic neuroendocrine tumor: Well-differentiated PanNENs, termed pancreatic neuroendocrine tumors (PanNETs), are categorized based on their Ki-67 labeling index or mitotic count: Grade 1 (G1): Ki-67 < 3% and <2 mitoses/10 high-power field (HPF); Grade 2 (G2): Ki-67 3–20% or 2–20 mitoses/10 HPF; and Grade 3 (G3): Ki-67 > 20% or >20 mitoses/10 HPF.