MKI67 and neuroendocrine neoplasm: The ones with a mitotic count of <2/10 high-power fields (HPF) and/or with a Ki-67 index of ≤2% are classified as the neuroendocrine tumor (NET) Grade I, whereas those with a mitotic count of 2/10 to 10/10 HPF and/or with a Ki 67 index between 3% and 20% are classified as NET Grade II.