MKI67 and digestive system mixed adenoneuroendocrine carcinoma: In this classification, grade 1 NETs (mitotic count < 2 per 10 high-power fields [HPFs]), grade 2 NETs (mitotic count 2–20 per 10 HPFs and/or Ki67 index > 20%), NEC (mitotic count > 20 per 10 HPFs and/or Ki67 index > 20%), and MANEC is defined as neoplasms comprised of both adenocarcinoma and NEC components in at least 30% of the tumor [2].