Ki-67 Index of 5% is Better Than 2% in Stratifying G1 and G2 of the World Health Organization Grading System in Pancreatic Neuroendocrine Tumors

ObjectiveThe World Health Organization (WHO) grading system for the stratification of G1 and G2 pancreatic neuroendocrine tumors (pNETs) using an optimal Ki-67 index cutoff is still controversial. The present study aimed at finding one optimal Ki-67 cutoff value that distinguishes G1 and G2 tumors b