PD-L1 and IDO1 expression and tumor-infiltrating lymphocytes in osteosarcoma patients: comparative study of primary and metastatic lesions

• DOI: 10.1007/s00432-020-03242-6
• Publication Date: 2020-05-09T18:04:28Z
• Authors: Yu Toda; Kenichi Kohashi; Yuichi Yamada; Masato Yoshimoto; Shin Ishihara; Yoshihiro Ito; Takeshi Iwasaki; Hidetaka Yamamoto; Yoshihiro Matsumoto; Yasuharu Nakashima; Masaaki Mawatari; Yoshinao Oda
• Keywords: Adult; Male; 0301 basic medicine; Osteosarcoma; Adolescent; Bone Neoplasms; Middle Aged; Prognosis; B7-H1 Antigen; 3. Good health; Young Adult; 03 medical and health sciences; Lymphocytes, Tumor-Infiltrating; T-Lymphocyte Subsets; Tumor Microenvironment; Humans; Indoleamine-Pyrrole 2,3,-Dioxygenase; Female; Child; Neoplasm Staging

Programmed death ligand 1 (PD-L1) and indoleamine 2,3-dioxygenase 1 (IDO1) are immunosuppressive proteins known to be associated with poor prognosis in various cancers. However, their expression and clinical relevance in osteosarcoma remain unknown. In this study, the relationships of PD-L1 and IDO1 expression with clinicopathological features and prognosis were explored.The expression of PD-L1, IDO1, CD3, CD4, and CD8 in 112 formalin-fixed, paraffin-embedded tumor tissues collected by biopsy or surgical resection from 56 osteosarcoma patients was evaluated immunohistochemically. Moreover, four osteosarcoma cell lines were evaluated for the effects of IFNγ on PD-L1 and IDO1 mRNA expression by real-time reverse-transcription polymerase chain reaction.In pre-neoadjuvant chemotherapy (NAC) primary specimens, 10 cases (17%) showed PD-L1 expression and 12 (21%) showed IDO1 expression. Six of ten cases (60%) with PD-L1 positivity co-expressed IDO1. In post-NAC metastatic lesions, the frequency of immunoexpression of PD-L1 and IDO1 was increased compared with that in pre-NAC specimens. PD-L1 and/or IDO1 expression was not associated with poor prognosis. PD-L1 immunoexpression was significantly associated with the infiltration of CD3+ T cells, CD4+ T cells, and CD8+ T cells; while, IDO1 immunoexpression was significantly associated with the infiltration of CD3+ T cells and CD4+ T cells. In all osteosarcoma cell lines, PD-L1 and IDO1 expression was upregulated by stimulation with IFNγ.Our results suggest that the PD-L1 and IDO1 immune checkpoint inhibitors may provide clinical benefit in osteosarcoma patients with metastatic lesions after conventional chemotherapy.