Grading of neuroendocrine neoplasms: mitoses and Ki-67 are both essential.

Background: The current WHO classification for neuroendocrine neoplasms (NEN) of the gastrointestinal tract requires Ki-67 and mitotic index for grading. However, both indexes might be conflicting as far as grade is concerned. In this study, we investigate which of the two indexes is most informative to predict survival.