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Digital PCR quantification of ultrahigh ERBB2 copy number identifies poor breast cancer survival after trastuzumab

Meng, Pei LU ; Dalal, Hina LU orcid ; Chen, Yilun LU ; Brueffer, Christian LU orcid ; Gladchuk, Sergii LU ; Alcaide, Miguel ; Ehinger, Anna LU orcid and Saal, Lao H LU orcid (2024) In npj Breast Cancer 10(1).
Abstract
HER2/ERBB2 evaluation is necessary for treatment decision-making in breast cancer (BC), however current methods have limitations and considerable variability exists. DNA copy number (CN) evaluation by droplet digital PCR (ddPCR) has complementary advantages for HER2/ERBB2 diagnostics. In this study, we developed a single-reaction multiplex ddPCR assay for determination of ERBB2 CN in reference to two control regions, CEP17 and a copy-number-stable region of chr. 2p13.1, validated CN estimations to clinical in situ hybridization (ISH) HER2 status, and investigated the association of ERBB2 CN with clinical outcomes. 909 primary BC tissues were evaluated and the area under the curve for concordance to HER2 status was 0.93 and 0.96 for ERBB2... (More)
HER2/ERBB2 evaluation is necessary for treatment decision-making in breast cancer (BC), however current methods have limitations and considerable variability exists. DNA copy number (CN) evaluation by droplet digital PCR (ddPCR) has complementary advantages for HER2/ERBB2 diagnostics. In this study, we developed a single-reaction multiplex ddPCR assay for determination of ERBB2 CN in reference to two control regions, CEP17 and a copy-number-stable region of chr. 2p13.1, validated CN estimations to clinical in situ hybridization (ISH) HER2 status, and investigated the association of ERBB2 CN with clinical outcomes. 909 primary BC tissues were evaluated and the area under the curve for concordance to HER2 status was 0.93 and 0.96 for ERBB2 CN using either CEP17 or 2p13.1 as reference, respectively. The accuracy of ddPCR ERBB2 CN was 93.7% and 94.1% in the training and validation groups, respectively. Positive and negative predictive value for the classic HER2 amplification and non-amplification groups was 97.2% and 94.8%, respectively. An identified biological “ultrahigh” ERBB2 ddPCR CN group had significantly worse survival within patients treated with adjuvant trastuzumab for both recurrence-free survival (hazard ratio, HR: 3.3; 95% CI 1.1–9.6; p = 0.031, multivariable Cox regression) and overall survival (HR: 3.6; 95% CI 1.1–12.6; p = 0.041). For validation using RNA-seq data as a surrogate, in a population-based SCAN-B cohort (NCT02306096) of 682 consecutive patients receiving adjuvant trastuzumab, the ultrahigh-ERBB2 mRNA group had significantly worse survival. Multiplex ddPCR is useful for ERBB2 CN estimation and ultrahigh ERBB2 may be a predictive factor for decreased long-term survival after trastuzumab treatment. (Less)
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author
; ; ; ; ; ; and
organization
publishing date
type
Contribution to journal
publication status
published
subject
keywords
ERBB2 amplification, Digital PCR, Breast Cancer, in situ hybridisation, HER2 Immunohistochemestry
in
npj Breast Cancer
volume
10
issue
1
article number
14
publisher
Nature Publishing Group
external identifiers
  • scopus:85185452056
  • pmid:38374091
ISSN
2374-4677
DOI
10.1038/s41523-024-00621-x
language
English
LU publication?
yes
id
12d92176-2798-4bcb-b9da-a0b02639a8ff
date added to LUP
2024-02-22 17:13:25
date last changed
2025-04-04 15:14:51
@article{12d92176-2798-4bcb-b9da-a0b02639a8ff,
  abstract     = {{HER2/ERBB2 evaluation is necessary for treatment decision-making in breast cancer (BC), however current methods have limitations and considerable variability exists. DNA copy number (CN) evaluation by droplet digital PCR (ddPCR) has complementary advantages for HER2/ERBB2 diagnostics. In this study, we developed a single-reaction multiplex ddPCR assay for determination of ERBB2 CN in reference to two control regions, CEP17 and a copy-number-stable region of chr. 2p13.1, validated CN estimations to clinical in situ hybridization (ISH) HER2 status, and investigated the association of ERBB2 CN with clinical outcomes. 909 primary BC tissues were evaluated and the area under the curve for concordance to HER2 status was 0.93 and 0.96 for ERBB2 CN using either CEP17 or 2p13.1 as reference, respectively. The accuracy of ddPCR ERBB2 CN was 93.7% and 94.1% in the training and validation groups, respectively. Positive and negative predictive value for the classic HER2 amplification and non-amplification groups was 97.2% and 94.8%, respectively. An identified biological “ultrahigh” ERBB2 ddPCR CN group had significantly worse survival within patients treated with adjuvant trastuzumab for both recurrence-free survival (hazard ratio, HR: 3.3; 95% CI 1.1–9.6; p = 0.031, multivariable Cox regression) and overall survival (HR: 3.6; 95% CI 1.1–12.6; p = 0.041). For validation using RNA-seq data as a surrogate, in a population-based SCAN-B cohort (NCT02306096) of 682 consecutive patients receiving adjuvant trastuzumab, the ultrahigh-ERBB2 mRNA group had significantly worse survival. Multiplex ddPCR is useful for ERBB2 CN estimation and ultrahigh ERBB2 may be a predictive factor for decreased long-term survival after trastuzumab treatment.}},
  author       = {{Meng, Pei and Dalal, Hina and Chen, Yilun and Brueffer, Christian and Gladchuk, Sergii and Alcaide, Miguel and Ehinger, Anna and Saal, Lao H}},
  issn         = {{2374-4677}},
  keywords     = {{ERBB2 amplification; Digital PCR; Breast Cancer; in situ hybridisation; HER2 Immunohistochemestry}},
  language     = {{eng}},
  month        = {{02}},
  number       = {{1}},
  publisher    = {{Nature Publishing Group}},
  series       = {{npj Breast Cancer}},
  title        = {{Digital PCR quantification of ultrahigh ERBB2 copy number identifies poor breast cancer survival after trastuzumab}},
  url          = {{http://dx.doi.org/10.1038/s41523-024-00621-x}},
  doi          = {{10.1038/s41523-024-00621-x}},
  volume       = {{10}},
  year         = {{2024}},
}