NETs are further classified based on their Ki-67 index into low-grade (NET G1, Ki-67 < 3%), medium-grade (NET G2, Ki-67 3-20%), and high-grade (NET G3, Ki-67 > 20%) tumors and neuroendocrine carcinomas (NEC) G3 with low differentiation [1]. Here, MKI67 is linked to neuroendocrine carcinoma.