title: Analysis of expression of programmed cell death 1 ligand 1 (PD-L1) in malignant pleural mesothelioma (MPM).
abstract: BACKGROUND
  The increasing incidence and poor outcome associated with MPM requires finding effective treatment for this disease. PD1/PD-L1 pathway plays a central role in tumor immune evasion and appears to be predictive and prognostic marker. PD-L1 is expressed in many different human cancers but its role in MPM has yet to be established. The aim of this study is to evaluate the expression of PD-L1 in MPM.
  
  
  METHODS
  119 MPM patients (p) from two institutions between November 2002 and February 2014 were reviewed. Formalin-fixed, paraffin-embedded tissue was stained with anti-PD-L1 (clone E1L3N). Cases showing more than 1% of tumor cells expression of PD-L1 were considered positive.
  
  
  RESULTS
  PD-L1 was analyzed in 77 p with tumor tissue available and was positive in 20.7% p (14 samples in membrane, 16 in cytoplasm and 4 in immune infiltrate). PD-L1 intensity was weak in 56.2%, moderate in 25% and strong in 18.7% p. There was a significant relationship between PD-L1 expression and histology (PD-L1 expression 37.5% in no-epithelioid tumor and 13.2% in epithelioid; p=0.033). The median survival in p PD-L1 positive was 4.79 vs 16.3 months in p PD-L1 negative (p=0.012).
  
  
  CONCLUSIONS
  We have shown PD-L1 is expressed in 20% of patients, associated with no epithelioid histology and poor prognostic in MPM. Our results suggest PD-L1 warrants further exploration in selecting p for immunotherapy.
authors.affiliation: Medical Oncology Service/Vall d´Hebron Institute Oncology, Vall d'Hebron University Hospital, Barcelona, Spain.
authors.forename: Susana
authors.initials: S
authors.lastname: Cedrés
authors.affiliation: Medical Oncology Service/ 12 de Octubre University Hospital, Madrid, Spain.
authors.forename: Santiago
authors.initials: S
authors.lastname: Ponce-Aix
authors.affiliation: Medical Oncology Service/ 12 de Octubre University Hospital, Madrid, Spain.
authors.forename: Jon
authors.initials: J
authors.lastname: Zugazagoitia
authors.affiliation: Pathology Department/ Vall d'Hebron University Hospital, Barcelona, Spain.
authors.forename: Irene
authors.initials: I
authors.lastname: Sansano
authors.affiliation: Pathology Department/12 de Octubre University Hospital, Madrid, Spain.
authors.forename: Ana
authors.initials: A
authors.lastname: Enguita
authors.affiliation: Medical Oncology Service/Vall d´Hebron Institute Oncology, Vall d'Hebron University Hospital, Barcelona, Spain.
authors.forename: Alejandro
authors.initials: A
authors.lastname: Navarro-Mendivil
authors.affiliation: Medical Oncology Service/Vall d´Hebron Institute Oncology, Vall d'Hebron University Hospital, Barcelona, Spain.
authors.forename: Alex
authors.initials: A
authors.lastname: Martinez-Marti
authors.affiliation: Medical Oncology Service/Vall d´Hebron Institute Oncology, Vall d'Hebron University Hospital, Barcelona, Spain.
authors.forename: Pablo
authors.initials: P
authors.lastname: Martinez
authors.affiliation: Medical Oncology Service/Vall d´Hebron Institute Oncology, Vall d'Hebron University Hospital, Barcelona, Spain.
authors.forename: Enriqueta
authors.initials: E
authors.lastname: Felip
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D060890:B7-H1 Antigen / Q000235:genetics / Q000378:metabolism*; D005260:Female; D005500:Follow-Up Studies; D015870:Gene Expression; D006801:Humans; D007150:Immunohistochemistry; D053208:Kaplan-Meier Estimate; D008175:Lung Neoplasms / Q000235:genetics / Q000378:metabolism* / Q000401:mortality / Q000473:pathology / Q000628:therapy; D008297:Male; D008654:Mesothelioma / Q000235:genetics / Q000378:metabolism* / Q000401:mortality / Q000473:pathology / Q000628:therapy; D000086002:Mesothelioma, Malignant; D008875:Middle Aged; D010997:Pleural Neoplasms / Q000235:genetics / Q000378:metabolism* / Q000401:mortality / Q000473:pathology / Q000628:therapy; D011379:Prognosis; D012307:Risk Factors
chemical_list: D060890:B7-H1 Antigen