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Review
. 2023 Apr 3:10:1176309.
doi: 10.3389/fmolb.2023.1176309. eCollection 2023.

Pathological identification of HER2-low breast cancer: Tips, tricks, and troubleshooting for the optimal test

Elham Sajjadi  1   2 , Elena Guerini-Rocco  1   2 , Elisa De Camilli  2 , Oriana Pala  2 , Giovanni Mazzarol  2 , Konstantinos Venetis  2 , Mariia Ivanova  2 , Nicola Fusco  1   2
Affiliations
Review

Pathological identification of HER2-low breast cancer: Tips, tricks, and troubleshooting for the optimal test

Elham Sajjadi et al. Front Mol Biosci. .

Abstract

The introduction of novel anti-HER2 antibody-drug conjugates (ADC) for the treatment of HER2-low breast cancers has transformed the traditional dichotomy of HER2 status to an expanded spectrum. However, the identification of HER2-low (i.e., immunohistochemistry (IHC) score 1 + or IHC score 2+, without gene amplification) tumors is challenged by methodological and analytical variables that might influence the sensitivity and reproducibility of HER2 testing. To open all possible therapeutic opportunities for HER2-low breast cancer patients the implementation of more accurate and reproducible testing strategies is mandatory. Here, we provide an overview of the existing barriers that may trouble HER2-low identification in breast cancer and discuss practical solutions that could enhance HER-low assessment.

Keywords: HER2; HER2-low; breast cancer; immunohistochemistry; in situ hybridization; pathology; precision medicine.

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Conflict of interest statement

NF has received honoraria for consulting, advisory role, speaker bureau, travel, and/or research grants from MSD, Boehringer Ingelheim, Novartis, Roche, AstraZeneca, Daiichi Sankyo, GlaxoSmithKline (GSK), Gilead, Diaceutics, Adicet Bio, and Sermonix. EGR has received honoraria for consulting, advisory role, speaker bureau, travel, and/or research grants from Thermo Fisher Scientific, Novartis, AstraZeneca, Roche, Biocartis, Exact Science, GSK, and Illumina. The remaining authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest.

Figures

FIGURE 1
FIGURE 1
Graphical representation of HER2 expression spectrum, with score definition and interpretation according to ASCO/CAP guidelines. ISH, in situ hybridization.
See this image and copyright information in PMC

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