The influence of immunohistochemistry on mRNA recovery from microdissected frozen and formalin-fixed, paraffin-embedded sections

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Laser-assisted microdissection (LAM) is now widely used to obtain specific cell populations from heterogeneous tissues. A major disadvantage of LAM is poor tissue morphology during microscopy, in part because coverslips are not used. Immunohistochemical labeling can improve identification of target cells but may affect the subsequent analysis of the microdissected tissue. We studied the effect of immunohistochemistry (IHC) on mRNA recovery from labeled cells after microdissection from both frozen and formalin-fixed, paraffin-embedded (FFPE) sections, using Melan-A and Ki-67 staining in lymph nodes with metastatic melanoma as a model. We developed rapid protocols for immunostaining in an attempt to limit loss of mRNA during procedures. A sensitive real-time quantitative reverse transcription-PCR was used to measure mRNA. We found a marked decrease in the mRNA yield from 500 microdissected cells from frozen and paraffin sections after immunostaining for both markers. Recovery of mRNA decreased by up to 89%, comparing the immunostained with the routinely stained sections. Interestingly, the ratio between mRNA for the two markers was similar in all stains, indicating that immunostained sections may be used for mRNA analysis. We also investigated the effect of storing membrane-mounted sections for microdissection under different conditions. Slides mounted with paraffin sections could be stored at room temperature for up to 90 days with no significant decrease in mRNA recovery.

Original languageEnglish
JournalDiagnostic Molecular Pathology
Volume13
Issue number4
Pages (from-to)224-233
Number of pages10
ISSN1052-9551
DOIs
Publication statusPublished - Dec 2004

    Research areas

  • Formalin-fixed, Frozen tissue, Immunohistochemistry, Laser-assisted microdissection, Membrane-mounted slides for microdissection, MRNA yield, Paraffin-embedded tissue, Real-time quantitative PCR

ID: 375144493