title: Is There Evidence for the Presence and Relevance of the PD-1/PD-L1 Pathway in Oral Squamous Cell Carcinoma? Hints From an Immunohistochemical Study.
abstract: OBJECTIVE
  To examine oral squamous cell carcinoma (OSCC) specimens for programmed death ligand-1 (PD-L1) expression and presence of programmed death-1 (PD-1)-positive tumor-infiltrating lymphocytes (TILs) and to determine possible clinicopathologic implications. It was hypothesized that PD-L1 expression and PD-1-positive TIL presence in OSCC would have no clinical relevance.
  
  
  METHODS
  The authors implemented a retrospective cohort study design. The study cohort was chosen in compliance with predefined inclusion criteria. Demographic, clinical, and histopathologic data were gathered. Tissue microarrays were obtained from paraffin-embedded OSCC specimens and analyzed immunohistochemically for PD-L1 expression and PD-1-positive TIL infiltration. PD-L1 positivity of OSCC specimens served as the predictor variable and neck node metastasis served as the primary outcome variable. Descriptive and inferential statistics were computed and the significance level was set at a P value less than or equal to .05.
  
  
  RESULTS
  The study sample was composed of 88 patients (48 men, 40 women; mean age, 61.34 yr). Marked PD-L1 expression was detected in 29% of OSCC specimens (26 of 88) and 83% of specimens (73 of 88) exhibited a high rate of PD-1-positive TIL infiltration. PD-L1 positivity of OSCC samples was significantly associated with the anatomic origin of OSCC (P = .039), presence of cervical metastasis (P = .039), and high PD-L1-positive TIL infiltration (P = .033).
  
  
  CONCLUSIONS
  A considerable proportion of OSCCs exhibited marked PD-L1 expression. This could be associated with clinical parameters. PD-L1 expression in OSCC might differ depending on its anatomic origin. PD-1-positive TILs could be detected in most OSCC specimens. These findings might indicate a potential role for the PD-1 and PD-L1 pathway in OSCC.
authors.affiliation: Resident, Department of Oral and Maxillofacial Surgery, Ludwig Maximilians University of Munich, Munich, Germany. Electronic address: matthias_troeltzsch@hotmail.com.
authors.forename: Matthias
authors.initials: M
authors.lastname: Troeltzsch
authors.affiliation: Medical Oncologist, Department of Medicine, Division of Medical Oncology and Hematology, School of Medicine and Dentistry, University of Rochester, Rochester; Unity Health System, Rochester, NY.
authors.forename: Timothy
authors.initials: T
authors.lastname: Woodlock
authors.affiliation: Medical Student, Department of Oral and Maxillofacial Surgery, Ludwig Maximilians University of Munich, Munich, Germany.
authors.forename: Alix
authors.initials: A
authors.lastname: Pianka
authors.affiliation: Consultant, Department of Oral and Maxillofacial Surgery, Ludwig Maximilians University of Munich, Munich, Germany.
authors.forename: Sven
authors.initials: S
authors.lastname: Otto
authors.affiliation: Consultant, Department of Oral and Maxillofacial Surgery, Georg August University of Göttingen, Göttingen, Germany.
authors.forename: Markus
authors.initials: M
authors.lastname: Troeltzsch
authors.affiliation: Professor and Department Chair, Department of Oral and Maxillofacial Surgery, Ludwig Maximilians University of Munich, Munich, Germany.
authors.forename: Michael
authors.initials: M
authors.lastname: Ehrenfeld
authors.affiliation: Professor, Department of Pathology, Ludwig Maximilians University of Munich, Munich, Germany.
authors.forename: Thomas
authors.initials: T
authors.lastname: Knösel
mesh_terms: D000368:Aged; D060890:B7-H1 Antigen / Q000032:analysis / Q000096:biosynthesis*; D002294:Carcinoma, Squamous Cell / Q000737:chemistry / Q000378:metabolism*; D015331:Cohort Studies; D005260:Female; D006801:Humans; D007150:Immunohistochemistry; D008297:Male; D008875:Middle Aged; D009062:Mouth Neoplasms / Q000737:chemistry / Q000378:metabolism*; D061026:Programmed Cell Death 1 Receptor / Q000032:analysis / Q000096:biosynthesis*; D012189:Retrospective Studies; D015398:Signal Transduction
chemical_list: D060890:B7-H1 Antigen; D061026:Programmed Cell Death 1 Receptor