Interlaboratory Variability of MIB1 Staining in Well Differentiated Pancreatic Neuroendocrine Tumors

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Introduction: In neuroendocrine tumors (NET) grading and staging are the only routinely performed procedures to judge prognosis. Proliferation index using MIB1 staining has been introduced to assess grading. There are discussions on cut-off definitions, automated counting and inter-observer variability.

Aim(s): To assess Inter-lab differences, we performed MIB1 staining in 3 different University Hospital based pathology laboratories on a TMA of a well characterized patient cohort, containing pancreatic NET of 61 patients.

Materials and methods: To calculate the proliferation index, number of positive tumour nuclei was divided by the total number of tumour nuclei. Labelling index was compared to mitotic counts in whole tissue sections and to outcome. Linear regression analysis and ROC analysis were performed.

Conference: 12th Annual ENETSConcerence (2015)

Presenting Author: Perren A

Authors: Blank A, Wehweck L, Marinoni I, Boos L, Schmitt A,

Keywords: MIB1, Ki67, grading, NET,