Comparison of Different Antibody Clones for Immunohistochemistry Detection of Programmed Cell Death Ligand 1 (PD-L1) on Non-Small Cell Lung Carcinoma

Appl Immunohistochem Mol Morphol. 2018 Feb;26(2):83-93. doi: 10.1097/PAI.0000000000000531.

Abstract

Programmed cell death ligand 1 (PD-L1) is a major immune checkpoint protein that mediates antitumor immune suppression and response. Preliminary data suggest that its detection using immunohistochemistry (IHC) in formalin-fixed and paraffin-embedded tissues may predict clinical response to PD-1/PD-L1 therapy. In diagnostic pathology, it is essential to count with a validated IHC that can reliably detect PD-L1-positive cases. The present study was conducted to compare and validate different PD-L1 commercial clones and identify which ones can be reliably used by surgical pathologist to detect PD-L1 expression in human cancer tissues. Eight commercial available PD-L1 clones were tested and compared with a noncommercial PD-L1 antibody clone 5H1. Western blot and IHC using cell lines and human tissues were used to validate these clones. From all PD-L1 antibodies, only the clones E1L3N, E1J2J, SP142, 28-8, 22C3, and SP263 passed the Western blot and IHC validation, providing similar pattern than the clone 5H1 and then they were tested in 259 non-small cell lung cancer cases placed in 9 tissue microarrays. Among all cases, only those with ≥2 cores were included (185 cases). Positive and significant correlation was found between the median PD-L1 H-score in tumor and stroma compartments, for all selected antibodies. Overall, 56 of 185 cases were detected as positive cases in malignant cells expressing membranous PD-L1 by all the clones. However, the clone SP263 identified more PD-L1-positive cases compared with the other clones. Our results show that clones E1L3N, E1J2J, SP142, 28-8, 22C3, and SP263 provide positive membrane staining pattern comparable with clone 5H1. These commercial clones are comparable, but a careful evaluation by the pathologist is necessary to minimize error of positive misinterpretations.

Publication types

  • Comparative Study
  • Research Support, N.I.H., Extramural
  • Research Support, Non-U.S. Gov't
  • Research Support, U.S. Gov't, Non-P.H.S.

MeSH terms

  • Antibodies, Monoclonal / metabolism*
  • B-Lymphocytes / physiology*
  • B7-H1 Antigen / immunology
  • B7-H1 Antigen / metabolism*
  • Biomarkers, Pharmacological / metabolism*
  • Carcinoma, Non-Small-Cell Lung / diagnosis
  • Carcinoma, Non-Small-Cell Lung / immunology
  • Carcinoma, Non-Small-Cell Lung / metabolism*
  • Clone Cells
  • HEK293 Cells
  • Humans
  • Immunohistochemistry / methods*
  • Lung Neoplasms / diagnosis
  • Lung Neoplasms / immunology
  • Lung Neoplasms / metabolism*
  • Predictive Value of Tests
  • Prognosis
  • Programmed Cell Death 1 Receptor / metabolism
  • Tissue Array Analysis

Substances

  • Antibodies, Monoclonal
  • B7-H1 Antigen
  • Biomarkers, Pharmacological
  • PDCD1 protein, human
  • Programmed Cell Death 1 Receptor