MKI67 and cancer: Based on the proliferative rate (mitotic rate and Ki-67 index) the well-differentiated NETs are further subdivided into a low grade (G1) and intermediate grade (G2) while grade 3 are classified as poorly differentiated endocrine carcinomas (G3) while the small cell and large cell carcinomas are classified as A type of neuroendocrine carcinoma (NEC) under poorly differentiated cancers [10].