MKI67 and neoplasm: As mentioned above, NETs are classified into 3 types (type I to III) and graded as G1, G2, and G3 based on prognostic parameters of the proliferative index Ki-67, the mitotic count (number of mitosis × high power field [HPF]: mm2 area within the tumor) (4) G1: Ki-67 ≤2%, <2 mitoses/10 HPF; G2: K-67 3%–20%, 2–20 mitoses/10 HPF, G3: Ki-67 >20%, >20 mitoses/10 HPF (17).