Cancer Diagnosis Program | Biorepositories and Biospecimen Research Branch

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Fresh Cut Versus Stored Cut Paraffin-embedded Tissue: Effect on Immunohistochemical Staining for Common Breast Cancer Markers.

Author(s): Forse CL, Pinnaduwage D, Bull SB, Mulligan AM, Andrulis IL

Publication: Appl Immunohistochem Mol Morphol, 2019, Vol. 27, Page 231-237

PubMed ID: 29553968 PubMed Review Paper? No

Purpose of Paper

Conclusion of Paper

Studies

1. Study Purpose

   This study investigated the effects of storing formalin-fixed paraffin-embedded (FFPE) breast tumor sections at -80°C rather than as blocks at room temperature on immunohistochemical (IHC) staining of breast cancer markers. Sixty-seven breast tumor (61 invasive ductal carcinomas, 4 invasive lobular carcinomas, 1 micropapillary carcinoma, 1 tubulolobular carcinoma) specimens were formalin-fixed and paraffin embedded (no details provided). Sections (4 μm) were cut from the paraffin blocks, placed in a light-resistant box, and stored at −80° for an average of 153.87 months (range, 9.93 to 14 y). The original blocks were stored at room temperature for the same duration. Stored sections and freshly-cut 4 μm sections were analyzed for immunohistochemical staining. Thirty-nine tumors were used for estrogen receptor (ER) analysis, 55 tumors were used for cytokeratin 5 (CK5) analysis, 39 tumors were used for human epidermal growth factor receptor 2 (HER2) analysis, 64 tumors were used for epidermal growth factor receptor (EGFR) analysis, and 54 tumors were used for Ki67 analysis. Slides were assessed by a single blinded pathologist. Immunostaining was scored using the Allred method for ER (0 to 2, negative; 3 to 8, positive), CK5 (≥4, positive), and EGFR (≥4, positive). ASCO/CAP guidelines were used to assess HER2 (0/1+, 2+, or 3+) and Ki67 scores were determined based on the proportion of cells stained of any intensity (cut-off of 20%).

   Summary of Findings:

   Very strong concordance was observed between sections freshly cut from FFPE blocks stored at room temperature and sections stored at -80°C for ER, HER2, CK5, and EGFR (0.97, 0.94, 0.96, 0.95; respectively) with chance-corrected agreements of 0.94 for ER, 0.86 for HER2, 0.92 for CK5, and 0.87 for EGFR; but concordance for Ki67 was 0.85 and moderate chance-corrected agreement of 0.67. Of the discordant pairs, one was called ER negative on the stored section but positive on the freshly cut section, two were called HER2 negative on fresh cut slides but equivocal on stored sections, two were called CK5 positive on stored sections but negative on freshly cut sections, two were called EGFR positive on stored sections but negative on freshly cut sections, and one tumor was called negative on the stored section but positive on the freshly cut section. For Ki67 analysis, seven were called high (≥ 20%) on stored sections but low on freshly cut sections and one was called low (< 20%) on stored sections but high on the freshly cut section. No major differences were noted between the staining patterns (location of staining or intensity) for any of the markers examined.

   Biospecimens

   • Tissue - Breast

   Preservative Types

   • Formalin

   Diagnoses:

   • Neoplastic - Carcinoma

   Platform:

   Analyte	Technology Platform
   Protein	Immunohistochemistry

   Pre-analytical Factors:

   Classification	Pre-analytical Factor	Value(s)
   Storage	Storage conditions	Block Sections
   Storage	Storage duration	9.93 to 14 y

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