Expression of Programmed Cell Death Ligand 1 (PD-L1) and Prevalence of Tumor-Infiltrating Lymphocytes (TILs) in Chordoma

Oncotarget. 2015 May 10;6(13):11139-49. doi: 10.18632/oncotarget.3576.

Abstract

Chordomas are primary malignant tumors of the notochord that are resistant to conventional chemotherapy. Expression of programmed cell death ligand 1 (PD-L1), prevalence of tumor-infiltrating lymphocytes (TILs), and their clinical relevance in chordoma remain unknown. We evaluated PD-L1 expression in three chordoma cell lines and nine chordoma tissue samples by western blot. Immunohistochemical staining was performed on a chordoma tissue microarray (TMA) that contained 78 tissue specimens. We also correlated the expression of PD-L1 and TILs with clinical outcomes. PD-L1 protein expression was demonstrated to be induced by IFN-γ in both UCH1 and UCH2 cell lines. Across nine human chordoma tissue samples, PD-L1 protein was differentially expressed. 94.9% of chordoma samples showed positive PD-L1 expression in the TMA. The expression score of PD-L1 for metastatic chordoma tumors was significant higher as compared with non-metastatic chordoma tumors. Expression of PD-L1 protein significantly correlates with the presence of elevated TILs, which correlates with metastasis. In summary, our study showed high levels of PD-L1 are expressed in chordoma, which is correlated with the prevalence of TILs. The current study suggests targeting PD-L1 may be a novel immunotherapeutic strategy for chordoma clinical trials.

Keywords: PD-L1; TILs; chordoma; immunotherapy.

Publication types

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

MeSH terms

  • Adult
  • Aged
  • Aged, 80 and over
  • B7-H1 Antigen / metabolism*
  • Blotting, Western
  • Chordoma / immunology*
  • Chordoma / metabolism
  • Chordoma / mortality
  • Chordoma / pathology*
  • Female
  • Follow-Up Studies
  • Humans
  • Immunoenzyme Techniques
  • Lymphocytes, Tumor-Infiltrating / immunology*
  • Male
  • Middle Aged
  • Neoplasm Recurrence, Local / immunology*
  • Neoplasm Recurrence, Local / metabolism
  • Neoplasm Recurrence, Local / mortality
  • Neoplasm Recurrence, Local / pathology*
  • Neoplasm Staging
  • Prevalence
  • Prognosis
  • Survival Rate
  • Tissue Array Analysis
  • Tumor Cells, Cultured
  • Young Adult

Substances

  • B7-H1 Antigen