In endocrine tumors, a number of clinicopathologic criteria proved to be useful predictors of malignant behavior; these include: site of origin; tumor type; tumor size; invasion of nearby tissue or deep wall invasion; angioinvasion and invasion of perineural spaces; presence of spotty necrosis; overt cellular atypia; more than two mitoses in 10 HPFs; Ki-67 index of more than 100/10 HPFs, or more than 2%; loss of chromogranin A immunoreactivity; and nuclear p53 accumulation [4-23]. Here, MKI67 is linked to neoplasm.