PD-L1 expression in melanoma: A quantitative immunohistochemical antibody comparison

Joel C. Sunshine, Peter L. Nguyen, Genevieve J. Kaunitz, Tricia R. Cottrell, Sneha Berry, Jessica Esandrio, Haiying Xu, Aleksandra Ogurtsova, Karen B. Bleich, Toby C Cornish, Evan J. Lipson, Robert A. Anders, Janis M. Taube

Research output: Contribution to journalArticlepeer-review

Abstract

Purpose: PD-L1 expression in the pretreatment tumor microenvironment enriches for response to anti-PD-1/PD-L1 therapies. The purpose of this study was to quantitatively compare the performance of five monoclonal anti-PD-L1 antibodies used in recent landmark publications. Experimental Design: PD-L1 IHC was performed on 34 formalin-fixed paraffin-embedded archival melanoma samples using the 5H1, SP142, 28-8, 22C3, and SP263 clones. The percentage of total cells (including melanocytes and immune cells) demonstrating cell surface PD-L1 staining, as well as intensity measurements/H-scores, were assessed for each melanoma specimen using a computer-assisted platform. Staining properties were compared between antibodies. Results: Strong correlations were observed between the percentage of PD-L1(þ) cells across all clones studied (R2 = 0.81–0.96). When present, discordant results were attributable to geographic heterogeneity of the melanoma tissue section rather than differences in PD-L1 antibody staining characteristics. PD-L1 intensity/H-scores strongly correlated with percentage of PD-L1(þ) cells (R2 > 0.78, all clones). Conclusions: The 5H1, SP142, 28-8, 22C3, and SP263 clones all demonstrated similar performance characteristics when used in a standardized IHC assay on melanoma specimens. Reported differences in PD-L1 IHC assays using these antibodies are thus most likely due to assay characteristics beyond the antibody itself. Our findings also argue against the inclusion of an intensity/H-score in chromogenic PD-L1 IHC assays.

Original languageEnglish (US)
Pages (from-to)4938-4944
Number of pages7
JournalClinical Cancer Research
Volume23
Issue number16
DOIs
StatePublished - Aug 15 2017

ASJC Scopus subject areas

  • Oncology
  • Cancer Research

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