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Characterisation of HER heterodimers in breast cancer using in situ proximity ligation assay

Barros, Fabr�cio F.T.; Abdel-Fatah, Tarek M.A.; Moseley, Paul; Nolan, Christopher C.; Durham, Alice C.; Rakha, Emad A.; Chan, Stephen; Ellis, Ian O.; Green, Andrew R.

Characterisation of HER heterodimers in breast cancer using in situ proximity ligation assay Thumbnail


Fabr�cio F.T. Barros

Tarek M.A. Abdel-Fatah

Paul Moseley

Christopher C. Nolan

Alice C. Durham

Professor of Breast Cancer Pathology

Stephen Chan


HER2 plays an important role in breast cancer progression and provides predictive and prognostic information. HER2 receptor family members function through dimerisation, which can lead to impact on cell function, growth and differentiation; however, their value in breast cancer development remains to be defined. This study aims to examine the relationships of HER2 heterodimers to breast cancer characteristics in trastuzumab naïve and treated cases. HER2 protein (IHC), HER2 gene (chromogenic ISH) and HER2 heterodimerisation status [chromogenic in situ proximity ligation assay (PLA)] were assessed in two breast cancer series prepared in tissue microarray (TMA) format. A range of signals/cell for each HER2 heterodimer was detected (0–34.6 signals/cell). The vast majority of cases with HER2 heterodimers showed HER2 gene amplification and/or protein expression. There was an association between HER2 dimerisation with HER3 and HER4 and their protein expression level but no such association was found in with HER1 (EGFR). Of the HER2+ cases, 74, 66, and 58 % showed heterodimers with EGFR, HER3 and HER4, respectively. 51 % of HER2+ tumours expressed all three heterodimers whereas 23 % of the cases did not show expression of any of the three heterodimers. There was an inverse association between the presence and levels of HER2 heterodimers and hormone receptor expression in HER2+ tumours. Tumours exhibiting high levels of HER2 heterodimers demonstrated aggressive clinicopathological features and poor outcome. In the HER2+ cases, dimerisation with EGFR and HER3 but not with HER4 showed an association with aggressive features. There was no association between HER2 heterodimers with patient breast cancer-specific survival or recurrence in HER2+ breast cancer in those patients receiving trastuzumab or not. Our results demonstrate that HER2 dimerisation is a complex process that may underlie the biological heterogeneity of HER2 positive tumours and may identify patients suitable for a specific targeted therapy but does not predict patient outcome for those receiving trastuzumab. PLA proved to be a useful tool for detecting, visualising and quantifying the frequency of protein–protein interactions in archival formalin-fixed paraffin-embedded tissue samples.

Journal Article Type Article
Acceptance Date Feb 6, 2014
Online Publication Date Feb 21, 2014
Publication Date 2014-04
Deposit Date Oct 17, 2018
Publicly Available Date Oct 18, 2018
Journal Breast Cancer Research and Treatment
Print ISSN 0167-6806
Electronic ISSN 1573-7217
Publisher BMC
Peer Reviewed Peer Reviewed
Volume 144
Issue 2
Pages 273-285
Public URL
Publisher URL