title: Programmed cell death ligand 1 expression in osteosarcoma.
abstract: Programmed cell death ligand 1 (PDL1, also known as B7H1) is a cell-surface protein that suppresses the cytotoxic CD8(+) T-cell-mediated immune response. PDL1 expression and its clinical relevance in sarcomas are not well understood. Therefore, we sought to measure RNA expression levels for PDL1 in 38 clinically annotated osteosarcoma tumor samples and aimed to determine if PDL1 expression correlates with clinical features and tumor-infiltrating lymphocytes (TIL). Quantitative real-time RT-PCR for PDL1 was optimized in 18 cell lines, of which 5 were osteosarcoma derived. qRT-PCR results were validated via flow cytometry and immunohistochemistry (IHC) in select cell lines. Total RNA was isolated from 38 human osteosarcoma samples for qRT-PCR analysis. Clinical data were sorted, and significance was determined by the Student t test. TILs were examined in patient samples by tissue microarray hematoxylin-eosin staining. We confirmed the constitutive PDL1 mRNA expression in cell lines by qRT-PCR, flow cytometry, and IHC. Across human osteosarcoma samples, PDL1 mRNA gene expression ranged over 4 log (>5,000-fold difference). Relative expression levels were evaluated against clinical factors such as age/gender, metastasis, recurrence, chemotherapy, percentage of necrosis, and survival; no significant associations were identified. The presence of TILs was associated with high PDL1 expression (R(2) = 0.37; P = 0.01). In summary, we developed an RNA-based assay to determine PDL1 expression levels, and we show, for the first time, that high levels of PDL1 are expressed in a subset of osteosarcoma, and PDL1 expression is positively correlated with TILs. Multiple agents targeting PD1/PDL1 are in clinical development, and this may be a novel immunotherapeutic strategy for osteosarcoma clinical trials.
authors.affiliation: Sarcoma Biology Laboratory, Center for Sarcoma and Connective Tissue Oncology, Massachusetts General Hospital, Boston, United States.
authors.forename: Jacson K
authors.initials: JK
authors.lastname: Shen
authors.affiliation: Division of Hematology and Oncology, Massachusetts General Hospital, Boston, United States.
authors.forename: Gregory M
authors.initials: GM
authors.lastname: Cote
authors.affiliation: Division of Hematology and Oncology, Massachusetts General Hospital, Boston, United States.
authors.forename: Edwin
authors.initials: E
authors.lastname: Choy
authors.affiliation: Sarcoma Biology Laboratory, Center for Sarcoma and Connective Tissue Oncology, Massachusetts General Hospital, Boston, United States.
authors.forename: Pei
authors.initials: P
authors.lastname: Yang
authors.affiliation: Division of Hematology and Oncology, Massachusetts General Hospital, Boston, United States.
authors.forename: David
authors.initials: D
authors.lastname: Harmon
authors.affiliation: Sarcoma Biology Laboratory, Center for Sarcoma and Connective Tissue Oncology, Massachusetts General Hospital, Boston, United States.
authors.forename: Joseph
authors.initials: J
authors.lastname: Schwab
authors.affiliation: Department of Pathology, Massachusetts General Hospital, Boston, United States.
authors.forename: G Petur
authors.initials: GP
authors.lastname: Nielsen
authors.affiliation: Department of Pathology, Massachusetts General Hospital, Boston, United States.
authors.forename: Ivan
authors.initials: I
authors.lastname: Chebib
authors.affiliation: Monoclonal Antibody and Immunotherapy Laboratory, Department of Surgery, Massachusetts General Hospital, Boston, MA, United States.
authors.forename: Soldano
authors.initials: S
authors.lastname: Ferrone
authors.affiliation: Monoclonal Antibody and Immunotherapy Laboratory, Department of Surgery, Massachusetts General Hospital, Boston, MA, United States.
authors.forename: Xinhui
authors.initials: X
authors.lastname: Wang
authors.affiliation: Monoclonal Antibody and Immunotherapy Laboratory, Department of Surgery, Massachusetts General Hospital, Boston, MA, United States.
authors.forename: Yangyang
authors.initials: Y
authors.lastname: Wang
authors.affiliation: Sarcoma Biology Laboratory, Center for Sarcoma and Connective Tissue Oncology, Massachusetts General Hospital, Boston, United States.
authors.forename: Henry
authors.initials: H
authors.lastname: Mankin
authors.affiliation: Sarcoma Biology Laboratory, Center for Sarcoma and Connective Tissue Oncology, Massachusetts General Hospital, Boston, United States.
authors.forename: Francis J
authors.initials: FJ
authors.lastname: Hornicek
authors.affiliation: Sarcoma Biology Laboratory, Center for Sarcoma and Connective Tissue Oncology, Massachusetts General Hospital, Boston, United States.
authors.forename: Zhenfeng
authors.initials: Z
authors.lastname: Duan
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D060890:B7-H1 Antigen / Q000096:biosynthesis* / Q000235:genetics; D014408:Biomarkers, Tumor / Q000096:biosynthesis / Q000235:genetics; D001859:Bone Neoplasms / Q000276:immunology* / Q000628:therapy; D002648:Child; D005260:Female; D015870:Gene Expression; D006801:Humans; D008175:Lung Neoplasms / Q000276:immunology / Q000556:secondary; D016246:Lymphocytes, Tumor-Infiltrating / Q000276:immunology; D008297:Male; D008875:Middle Aged; D009363:Neoplasm Proteins / Q000096:biosynthesis / Q000235:genetics; D012516:Osteosarcoma / Q000276:immunology* / Q000556:secondary / Q000628:therapy; D011379:Prognosis; D012333:RNA, Messenger / Q000235:genetics; D012334:RNA, Neoplasm / Q000235:genetics; D060888:Real-Time Polymerase Chain Reaction / Q000379:methods; D016019:Survival Analysis; D014407:Tumor Cells, Cultured; D055815:Young Adult
chemical_list: D060890:B7-H1 Antigen; D014408:Biomarkers, Tumor; C423236:CD274 protein, human; D009363:Neoplasm Proteins; D012333:RNA, Messenger; D012334:RNA, Neoplasm