title: Diagnostic challenges of motility disorders: optimal detection of CD117+ interstitial cells of Cajal.
abstract: OBJECTIVE
  Several gastrointestinal motility diseases are associated with altered numbers of interstitial cells of Cajal (ICC), and testing for alterations in numbers of ICC has been proposed as one way to improve routine diagnosis in motility diseases. However, the protocols currently used to visualize ICC in formalin-fixed paraffin-embedded (FFPE) tissue using antibodies to CD117 have not been optimized for studying motility disorders. The aims of this study were therefore to determine the optimal protocol using FFPE tissue, determine normal values for ICC in non-neoplastic human colon, and compare results with those obtained using immunofluorescence (IF).
  
  
  RESULTS
  Non-neoplastic tissue was collected from patients undergoing resection for colonic cancer and fixed for both light (FFPE) and IF testing. Sections were processed for standard immunohistochemistry using different primary antibodies in conjunction with variations in antigen retrieval [ethylenediamine tetraacetricacid (EDTA), citrate], antibody dilution, blocking and detection (Mach2, Mach3, Envision+). Best results were obtained with EDTA retrieval, the DAKO CD117 antibody and Mach3 detection.
  
  
  CONCLUSIONS
  The optimized protocol presented improved CD117 detection in FFPE tissues and showed good concordance with overall localization of CD117-immunoreactive ICC as detected by IF. As such, this protocol may be more useful than current diagnostic procedures in motility disorders.
authors.affiliation: Division of Experimental Pathology, Mayo Clinic, Rochester, MN 55905, USA.
authors.forename: Megan M
authors.initials: MM
authors.lastname: Garrity
authors.forename: Simon J
authors.initials: SJ
authors.lastname: Gibbons
authors.forename: Thomas C
authors.initials: TC
authors.lastname: Smyrk
authors.forename: Jean Marie
authors.initials: JM
authors.lastname: Vanderwinden
authors.forename: Pedro Julian
authors.initials: PJ
authors.lastname: Gomez-Pinilla
authors.forename: Anoop
authors.initials: A
authors.lastname: Nehra
authors.forename: Matthew
authors.initials: M
authors.lastname: Borg
authors.forename: Gianrico
authors.initials: G
authors.lastname: Farrugia
mesh_terms: D003106:Colon / Q000166:cytology*; D003248:Constipation / Q000175:diagnosis; D005769:Gastrointestinal Motility; D006801:Humans; D007150:Immunohistochemistry; D016612:Paraffin Embedding; D019009:Proto-Oncogene Proteins c-kit / Q000378:metabolism*
chemical_list: D019009:Proto-Oncogene Proteins c-kit