University Of Tasmania

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Multiplex immunohistochemistry/immunofluorescence (mIHC/IF) for PD-L1 testing in triple-negative breast cancer: A translational assay compared with conventional IHC

journal contribution
posted on 2023-05-21, 11:57 authored by Yeong, J, Tan, T, Zi Long ChowZi Long Chow, Cheng, Q, Lee, B, Seet, A, Lim, JX, Lim, JCT, Ong, CCH, Thike, AA, Saraf, S, Tan, BYC, Poh, YC, Yee, S, Liu, J, Lim, E, Iqbal, J, Dent, R, Tan, PH

Background:Programmed death-ligand 1 (PD-L1) monoclonal antibody therapy has recently gained approval for treating metastatic triple-negative breast cancer (TNBC) -, in particular in the PD-L1+ patient subgroup of the recent IMpassion130 trial. The SP142 PD-L1 antibody clone was used as a predictive assay in this trial, but this clone was found to be an outlier in previous harmonisation studies in lung cancer.

Aims: To address the comparability of PD-L1 clones in TNBC, we evaluated the concordance between conventional immunohistochemistry (IHC) and multiplex immunohistochemistry/immunofluorescence (mIHC/IF) that allowed simultaneous quantification of three different PD-L1 antibodies (22C3, SP142 and SP263).

Methods: Our cohort comprised 25 TNBC cases, 12 non-small-cell lung carcinomas and 8 other cancers. EpCAM labelling was used to distinguish tumour cells from immune cells.

Results: Moderate-to-strong correlations in PD-L1 positivity were found between results obtained through mIHC/IF and IHC. Individual concordance rates in the study ranged from 67% to 100%, with Spearman's rank correlation coefficient values up to 0.88.

Conclusions: /IF represents a promising tool in the era of cancer immunotherapy, as it can simultaneously detect and quantify PD-L1 labelling with multiple antibody clones, and allow accurate evaluation of tumour and immune cells. Clinicians and pathologists require this information to predict patient response to anti-PD-1/PD-L1 therapy. The adoption of this assay may represent a significant advance in the management of therapeutically challenging cancers. Further analysis and assay harmonisation are essential for translation to a routine diagnostic setting.


Publication title

Journal of Clinical Pathology










Tasmanian School of Medicine


British Medical Association

Place of publication

United Kingdom

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© Author(s) (or their employer(s)) 2020. No commercial re-use. See rights and permissions. Published

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Socio-economic Objectives

Treatment of human diseases and conditions