The Immunohistochemical Expression of Programmed Death Ligand 1 (PD-L1) Is Affected by Sample Overfixation.
Author(s): Barberà A, Marginet Flinch R, Martin M, Mate JL, Oriol A, Martínez-Soler F, Santalucia T, Fernández PL
Publication: Appl Immunohistochem Mol Morphol, 2020, Vol. , Page
PubMed ID: 32134754 PubMed Review Paper? No
Purpose of Paper
This paper investigated the effects of fixation duration (12-96 h) on programmed death receptor ligand (PD-L1) staining using two different antibodies on tonsil tissue specimens.
Conclusion of Paper
There was no effect of fixation time up to 72 h on the number of sections determined to be suboptimally stained for PD-L1 but a significantly higher percentage of specimens fixed for 96 hours were classified as suboptimal for both PD-L1 antibodies.
Studies
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Study Purpose
This study investigated the effects of fixation duration on programmed death receptor ligand (PD-L1) staining using two different antibodies on tonsil tissue specimens. Twenty-two 0.5 cm thick specimens obtained during tonsillectomy (no diagnosis provided) were fixed in neutral buffered formalin for 12, 24, 48, 72, or 96 h (including the final 120 minutes of in-processor fixation) and paraffin-embedded in an automated processor. Three 3 mm tissue cores from each specimen were arrayed into a paraffin block and sectioned. Sections were stained in an autostainer with the SP142 and SP263 antibodies against PD-L1. Two pathologists evaluated each spot and classified specimens as optimally stained when 90% of the observed macrophages and T-cells had moderate to intense staining (+1 or +2) in germinal centers, there was intense staining (+2) of some epithelial squamous cells, and no staining in cells of interfollicular regions with no background staining. Sections not meeting these criteria were determined to be suboptimally stained.
Summary of Findings:
A significantly higher percentage of specimens fixed for 96 hours were classified as suboptimally stained compared to specimens fixed for 12-72 h h (15.6% versus <6%, P<0.0001). When data was separated by antibody, 20.8% and 10.4% were suboptimally stained when fixed for 96 h using the SP142 antibody and SP263 antibodies, respectively (P=0.046). There were no statistical differences between the two antibodies in number of sections determined to be suboptimally stained for fixation times from 12-72 h (range from 2.8%-6.1%).
Biospecimens
Preservative Types
- Formalin
Diagnoses:
- Not specified
Platform:
Analyte Technology Platform Protein Tissue microarray Protein Immunohistochemistry Pre-analytical Factors:
Classification Pre-analytical Factor Value(s) Biospecimen Preservation Time in fixative 12 h
24 h
48 h
72 h
96 h
Immunohistochemistry Specific Targeted peptide/protein PD-L1
Immunohistochemistry Specific Type of antibody Two antibodies compared