Factors affecting immunoreactivity in long-term storage of formalin-fixed paraffin-embedded tissue sections

Federica Grillo, Simona Pigozzi, Paola Ceriolo, Paola Calamaro, Roberto Fiocca, Luca Mastracci

Research output: Contribution to journalArticlepeer-review


Antigen decay in archival formalin-fixed paraffin-embedded (FFPE) tissue sections for immunohistochemistry is a well-known phenomenon which may have repercussions on translational and research studies and length of storage time appears fundamental. The aim of this study was to evaluate all possible factors which may lead to antigen decay on a prospective standardized collection of human tissues with a panel of 14 routinely used antibodies. Serial slide sections from FFPE control tissues were stored using different methods (routine storage at room temperature, Parafilm® protected, paraffin coated and cold stored at 4 °C) and for different time periods: 1, 6, 9, 12, 24 and 36 months. Immunohistochemistry was performed at each time cutoff simultaneously on stored sections and on freshly cut sections using a panel of 14 antibodies. Immunoreactivity was compared with immunoreactions performed at time zero. Reduction in immunostaining was observed for a subset of antibodies (CD3, CD 31, CD117, estrogen and progesterone receptors, Ki67, p53, TTF-1, vimentin) while for others (smooth muscle actin, keratins 7, 20, AE1/AE3, 34βE12), no antigen decay was observed. Loss of antigenicity was proportional to tissue section age and was dependent on mode of storage with cold storage slides being the least affected. All antigens with reductions in immunosignal were nuclear or membranous, and they all required heat pre-treatment for antigen retrieval. In contrast to results from other studies, when pre-analytical factors are strictly controlled and standardized, antigen decay seems to be restricted to nuclear or membrane antigens which require heat antigen retrieval.

Original languageEnglish
Pages (from-to)93-99
Number of pages7
JournalHistochemistry and Cell Biology
Issue number1
Publication statusPublished - Jul 18 2015


  • Antigen decay
  • Archival pathology
  • Immunohistochemistry
  • Paraffin section storage

ASJC Scopus subject areas

  • Cell Biology
  • Histology
  • Medical Laboratory Technology
  • Molecular Biology


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