Immunocytochemical evaluation of HER‐2/neu on fine‐needle aspirates from primary breast carcinomas

Abstract

Detection of HER-2/neu alterations is increasingly used in breast cancer patients for therapeutic purposes. This study examines the reliability of HER-2/neu immunocytochemical assessment on 66 cytospin smears obtained by fine-needle aspiration biopsy from breast cancer patients. Results were compared with those obtained by both fluorescence in situ hybridization (FISH) on fine-needle aspirate (FNA) and immunohistochemistry (IHC) on matched histologic section. Concordance between immunocytochemistry (ICC) and FISH was 78% and between ICC and IHC was 84%. Discordance mainly concerned seven unamplified cases that resulted positive by ICC and four cases scored negative by IHC but positive by ICC. Simultaneous assessment of HER-2/neu by ICC, IHC, and FISH was available in 24 cases; the concordance was 75%. In this study, the false positivity of immunocytochemical technique represents the major criticism. In our experience, FISH remains the most objective and powerful technique for HER-2/neu assessment on breast cancer FNAs.

Chromogenic In Situ Hybridization to Detect HER-2/neu Gene Amplification in Histological and ThinPrep®-Processed Breast Cancer Fine-Needle Aspirates: A Sensitive and Practical Method in the Trastuzumab Era

“…This issue is of major importance, because CISH could be particularly helpful in overcoming the problem of false-positive findings with ICC, one of the major criticisms of this methodology [25,26]. In our series, we found four positive cases (three score 3+, one score 2+) using ICC with LBC that were negative using IHC (score 1+) on the companion FFPE tissues and nonamplified by CISH both in ThinPrep and histological samples.…”

Immunocytochemistry and Fluorescence in Situ Hybridization in HER-2/neu Status in Cell Block Preparations

“…They surmised that this apparent "false positivity" was due to intrinsic limitations of the ICC/IHC assay, mainly related to tissue fixation and variability in the interpretation of the results. 13 Good concordance (> 90%) has been also reported when determining HER-2/neu status by FISH in cytologic specimens when compared to immunohistochemical or FISH results rendered on surgical specimens. 19,20 Studies comparing ICC and FISH results on cytologic preparations have reported variable concordance.…”

“…Studies validating the reliability of determining HER-2/neu status by ICC on cytologic specimens by comparing with immunohistochemical results performed on surgical specimens have been reported. [13][14][15][16][17] Overall, the studies have shown good concordance (> 90%); however, rare studies have reported a significantly higher incidence of HER-2/neu overexpression in cytologic material than in FFPE surgical specimens. 13,18 Nizzoli et al 13 found good concordance except for 4 cases that were negative by IHC but …”

Assessment of Thin-Layer Breast Aspirates for Immunocytochemical Evaluation of HER2 Status

“…18 Our findings are similar to those of a recent study by Nizzoli et al, who used FISH as their gold standard to assess HER2 evaluation by immunocytochemical methods. 19 …”