title: Comparison of formalin-free tissue fixatives: a proteomic study testing their application for routine pathology and research.
abstract: BACKGROUND
  Formalin-fixed, paraffin-embedded tissue is the routine processing method for diagnostics practiced in pathology departments worldwide.
  
  
  OBJECTIVE
  To determine the potential value of non-cross-linking, formalin-free tissue fixation for diagnostics in pathology and proteomic investigations.
  
  
  METHODS
  We tested 3 commercially available, formalin-free tissue fixatives-FineFIX, RCL2, and HOPE-in lung cancer specimens from 10 patients. The fixatives were evaluated for their effects on tissue morphology, protein recovery, and immunoreactivity for a selected panel of proteins differently expressed in lung cancer, using immunohistochemistry and Western blotting.
  
  
  RESULTS
  Tumor-cell analysis with hematoxylin-eosin worked equally well for all tested fixatives when compared with the standard formalin-fixed, paraffin-embedded procedure. Movat pentachrome stains showed comparable results for the different matrices and cellular proteins analyzed. The RCL2 (P = .01) and HOPE fixatives (P = .03) improved protein recovery when compared with formalin-fixed, paraffin-embedded or frozen tissues. Our data clearly show that the fixatives evaluated influenced immunoreactivity to matched, formalin-fixed, paraffin-embedded lung cancer tissue. In particular, membrane-bound proteins, such as epidermal growth factor receptor EGFR, can be detected more efficiently by immunohistochemistry and Western blotting.
  
  
  CONCLUSIONS
  We have demonstrated that formalin-free fixatives have the potential in routine pathology and research to replace formalin in histomorphology and protein preservation.
authors.affiliation: Institute of Pathology, Research Unit for Molecular Lung and Pleura Pathology, Medical University of Graz, Austria.
authors.forename: Hannelore
authors.initials: H
authors.lastname: Kothmaier
authors.forename: Daniela
authors.initials: D
authors.lastname: Rohrer
authors.forename: Elvira
authors.initials: E
authors.lastname: Stacher
authors.forename: Franz
authors.initials: F
authors.lastname: Quehenberger
authors.forename: Karl-Friedrich
authors.initials: KF
authors.lastname: Becker
authors.forename: Helmut H
authors.initials: HH
authors.lastname: Popper
mesh_terms: D014408:Biomarkers, Tumor / Q000032:analysis; D015153:Blotting, Western; D066246:ErbB Receptors / Q000032:analysis; D005404:Fixatives; D005557:Formaldehyde; D005629:Frozen Sections; D006801:Humans; D007150:Immunohistochemistry / Q000379:methods; D008175:Lung Neoplasms / Q000737:chemistry* / Q000175:diagnosis; D009363:Neoplasm Proteins / Q000032:analysis*; D016612:Paraffin Embedding; D010340:Pathology, Surgical / Q000379:methods; D040901:Proteomics / Q000379:methods; D016707:Tissue Fixation / Q000379:methods*
chemical_list: D014408:Biomarkers, Tumor; D005404:Fixatives; D009363:Neoplasm Proteins; D005557:Formaldehyde; C512478:EGFR protein, human; D066246:ErbB Receptors