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MIB-1 and MCM-2 Immunohistochemical Analysis Does Not Aid in Identification of Serrated Colorectal Polyps With Abnormal Proliferation

David Gray MD, Ellen C. Obermann MD, Mark Evans PhD, Arndt Hartmann MD, Kumarasen Cooper MD, Hagen Blaszyk MD
DOI: http://dx.doi.org/10.1309/E1BG63G8XAW32DNE 407-412 First published online: 1 March 2006

Abstract

We investigated the staining characteristics of serrated polyps with abnormal proliferation (SPAP) using MIB-1 and MCM-2 to determine if they could provide assistance in delineating SPAPs from traditional hyperplastic polyps (HPs). Using published morphologic criteria we reviewed H&E slides of 107 polyps from 80 patients. Thirty-nine (36.4%) polyps met the criteria for SPAP. Within a given region, polyps in the transverse colon had the largest percentage of SPAPs (50.0%) followed by the right colon (40.9%). The majority of SPAPs (82.1%) and HPs (72.1%) showed MIB-1 staining confined to the basal third of the crypts. The majority of SPAPs (59.0%) and HPs (52.9%) showed MCM-2 staining extending into the apical third of the crypts. We do not recommend MIB-1 or MCM-2 staining to differentiate SPAPs from conventional HPs, since staining characteristics are not significantly different between the 2 groups, and frequent variable crypt staining within a given polyp is difficult to interpret.

Key Words:
  • Hyperplastic polyp
  • Serrated polyp
  • Serrated neoplasia pathway
  • MIB-1
  • MCM-2