PCR-based analysis of PD-L1 RNA expression in lung cancer: comparison with commonly used immunohistochemical assays.
Immune checkpoint inhibitors
Non-small cell lung cancer
PD-L1 RNA expression
PD-L1 immunohistochemistry
Journal
Annals of diagnostic pathology
ISSN: 1532-8198
Titre abrégé: Ann Diagn Pathol
Pays: United States
ID NLM: 9800503
Informations de publication
Date de publication:
Aug 2022
Aug 2022
Historique:
received:
28
02
2022
revised:
20
04
2022
accepted:
02
05
2022
pubmed:
15
5
2022
medline:
29
6
2022
entrez:
14
5
2022
Statut:
ppublish
Résumé
PD-L1 testing is currently performed by immunohistochemistry (IHC). We questioned whether the results of PCR-based measurement of PD-L1 RNA expression correlate with IHC scores obtained by different commercial assays. 167 consecutive non-squamous non-small cell lung carcinomas (NSCLCs) were analyzed for PD-L1 RNA expression and 22C3, SP263, and SP142 IHC scoring using recommended cut-offs. RNA expression was divided into low, moderate, and high categories. RNA and protein expression demonstrated moderate correlation as continuous variables. Using prespecified RNA cut-offs, PCR testing showed a high negative predictive value towards the IHC analysis: the share of PD-L1 protein-negative tumors among cases classified as PD-L1-low by the PCR test reached 92-99% for all three antibodies. Meanwhile, about half of cases with moderate to high PD-L1 RNA expression had IHC staining in less than 1% tumor cells as determined by 22C3 or SP263 antibodies. Among the 51 discordant cases, which had <1% tumor staining by both 22C3 and SP263 clones but high RNA level, 29 (57%) showed ≥1% positive immune cells by SP263 and/or 22C3, 14 cases (27%) had detectable IHC expression in 0.1-0.9% tumor or immune cells by SP263 and/or 22C3, and 8 (16%) were entirely negative by IHC. Some NSCLCs demonstrate readily detectable PD-L1 expression on the level of RNA, but fall below commonly accepted cut-offs by IHC. It remains to be studied whether these discrepancies are attributed to technical or biological reasons. Clinical sensitivity of these tumors to immune therapy deserves additional investigations.
Sections du résumé
BACKGROUND
BACKGROUND
PD-L1 testing is currently performed by immunohistochemistry (IHC). We questioned whether the results of PCR-based measurement of PD-L1 RNA expression correlate with IHC scores obtained by different commercial assays.
MATERIALS AND METHODS
METHODS
167 consecutive non-squamous non-small cell lung carcinomas (NSCLCs) were analyzed for PD-L1 RNA expression and 22C3, SP263, and SP142 IHC scoring using recommended cut-offs. RNA expression was divided into low, moderate, and high categories.
RESULTS
RESULTS
RNA and protein expression demonstrated moderate correlation as continuous variables. Using prespecified RNA cut-offs, PCR testing showed a high negative predictive value towards the IHC analysis: the share of PD-L1 protein-negative tumors among cases classified as PD-L1-low by the PCR test reached 92-99% for all three antibodies. Meanwhile, about half of cases with moderate to high PD-L1 RNA expression had IHC staining in less than 1% tumor cells as determined by 22C3 or SP263 antibodies. Among the 51 discordant cases, which had <1% tumor staining by both 22C3 and SP263 clones but high RNA level, 29 (57%) showed ≥1% positive immune cells by SP263 and/or 22C3, 14 cases (27%) had detectable IHC expression in 0.1-0.9% tumor or immune cells by SP263 and/or 22C3, and 8 (16%) were entirely negative by IHC.
CONCLUSION
CONCLUSIONS
Some NSCLCs demonstrate readily detectable PD-L1 expression on the level of RNA, but fall below commonly accepted cut-offs by IHC. It remains to be studied whether these discrepancies are attributed to technical or biological reasons. Clinical sensitivity of these tumors to immune therapy deserves additional investigations.
Identifiants
pubmed: 35567888
pii: S1092-9134(22)00070-3
doi: 10.1016/j.anndiagpath.2022.151968
pii:
doi:
Substances chimiques
Antibodies
0
B7-H1 Antigen
0
Biomarkers, Tumor
0
RNA
63231-63-0
Types de publication
Journal Article
Langues
eng
Sous-ensembles de citation
IM
Pagination
151968Informations de copyright
Copyright © 2022 Elsevier Inc. All rights reserved.