Estrogen receptor, progesterone receptor, and human epidermal growth factor receptor 2 expression in breast cancer FNA cell blocks and paired histologic specimens: A large retrospective study

• Published in: Cancer cytopathology 2016-11, Vol.124 (11), p.828-835
• Main Authors: Vohra, Poonam, Buelow, Benjamin, Chen, Yunn‐Yi, Serrano, Maria, Vohra, Manjiv Singh, Berry, Anna, Ljung, Britt‐Marie
• Format: Article
• Language: English
• Subjects: Agreements; Biomarkers, Tumor; Biopsy, Fine-Needle - methods; Breast cancer; Breast Neoplasms - diagnosis; Breast Neoplasms - metabolism; Epidermal growth factor; estrogen receptor (ER); Estrogens; Female; fluorescence in situ hybridization (FISH); Gene Amplification; Gene Expression; human epidermal growth factor receptor 2 (HER2); Humans; immunohistochemistry; Immunohistochemistry - methods; In Situ Hybridization, Fluorescence; progesterone receptor (PR); Prognosis; Receptor, ErbB-2 - genetics; Receptor, ErbB-2 - metabolism; Receptors, Estrogen - genetics; Receptors, Estrogen - metabolism; Receptors, Progesterone - genetics; Receptors, Progesterone - metabolism; Reproducibility of Results; Sensitivity and Specificity
• ISSN: 1934-662X; 1934-6638
• DOI: 10.1002/cncy.21745

BACKGROUND Molecular analysis represents an increasingly important component of the pathologic examination of tumor specimens. Notably, the characterization of estrogen receptor (ER), progesterone receptor (PR), and human epidermal growth factor receptor 2 (HER2) expression in breast cancer specimens provides critical prognostic and predictive information. The objective of the current study was to compare the concordance of these markers as determined on fine‐needle aspiration (FNA) cell blocks compared with tissue blocks prepared from surgical specimens. METHODS A total of 134 cases of breast carcinoma were identified from 2002 through 2014 with both FNA cell blocks (fixed in 10% formalin) and corresponding available tissue blocks and ER, PR, and HER2 were characterized in both specimens. Negative and positive concordances were determined for ER and PR in cell blocks compared with tissue blocks, and for HER2 immunohistochemistry on cell blocks and tissue blocks versus the corresponding reference method, fluorescence in situ hybridization (FISH). RESULTS Concordance for ER expression evaluated on a cell block compared with the corresponding tissue block was 96.2%. Concordance for PR expression was 77.5%. Overall agreement of HER2 FISH testing between cell blocks and tissue blocks was 96.7%. For both cell blocks and tissue blocks, HER2 expression by immunohistochemistry demonstrated ≥98% positive and negative concordance with the FISH reference method. CONCLUSIONS ER, PR, and HER2 determination on FNA‐acquired cell block (fixed exclusively in 10% formalin) showed excellent agreement for ER and HER2 and moderate agreement for PR with the corresponding tissue block. These findings support the equivalency of ER and HER2 evaluation performed on FNA cell blocks compared with surgical tissue blocks. Cancer Cytopathol 2016;124:828‐35. © 2016 American Cancer Society. The results of the current study demonstrate excellent agreement for estrogen receptor and human epidermal growth factor receptor 2 (HER2) and moderate agreement for progesterone receptor immunohistochemistry performed on cell block compared with tissue block material. All HER2‐amplified cases (as determined by fluorescence in situ hybridization) were detected as either equivocal or positive HER2 immunohistochemistry staining in the same specimen on both cell and tissue blocks.