RT Journal Article
SR Electronic
T1 Multiplex immunohistochemistry/immunofluorescence (mIHC/IF) for PD-L1 testing in triple-negative breast cancer: a translational assay compared with conventional IHC
JF Journal of Clinical Pathology
JO J Clin Pathol
FD BMJ Publishing Group Ltd and Association of Clinical Pathologists
SP 557
OP 562
DO 10.1136/jclinpath-2019-206252
VO 73
IS 9
A1 Yeong, Joe
A1 Tan, Tira
A1 Chow, Zi Long
A1 Cheng, Qing
A1 Lee, Bernett
A1 Seet, Amanda
A1 Lim, Johnathan Xiande
A1 Lim, Jeffrey Chun Tatt
A1 Ong, Clara Chong Hui
A1 Thike, Aye Aye
A1 Saraf, Sahil
A1 Tan, Benjamin, Yong Cheng
A1 Poh, Yong Cheng
A1 Yee, Sidney
A1 Liu, Jin
A1 Lim, Elaine
A1 Iqbal, Jabed
A1 Dent, Rebecca
A1 Tan, Puay Hoon
YR 2020
UL http://jcp.bmj.com/content/73/9/557.abstract
AB 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 mIHC/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.