Robust Programmed Cell Death-1 Expression in a Subset of Ewing Sarcoma in Contrast to Ewing-like Sarcoma

Tamura A, Yoshida M, Yamamoto N, Nino N, Ichikawa T, Nakatani N, Nakamura S, Saito A, Kozaki A, Kishimoto K, Ishida K, Hasegawa D and Kosaka Y

Department of Hematology and Oncology, Children’s Cancer Center, Kobe Children’s Hospital, Japan
Department of Diagnostic Pathology, Kobe Children’s Hospital, Japan

^*Correspondance to: Akihiro Tamura 

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Abstract:

Background: Programmed cell death-1 (PD-1) and programmed cell death ligand-1 (PD-L1) expression may be surrogate markers for a response to immune checkpoint inhibitors. However, PD-1 and PD-L1 expressions in Ewing and Ewing-like sarcoma are poorly defined.Methods: Immunohistochemistry analysis was performed on formalin-fixed, paraffin-embedded pre-therapeutic tumor biopsies from patients with Ewing (n=11) and Ewing-like sarcoma (n=6). For the assessment of staining for PD-1/PD-L1 in tumor cells, rates forPD-1/PD-L1 positive tumor cells within total tumor cells: 0% as (–), >0% to <10% as (+), ≥ 10% to <50% as (++), ≥ 50% to <90% as (+++), and ≥ 90% as (++++), were used.Results: None of Ewing (n=11) and Ewing-like (n=6) sarcoma cells expressed PD-L1. PD-1 expressing tumor infiltrating lymphocytes were not prevalent both in Ewing and Ewing-like sarcoma. However, PD-1 was robustly expressed in 4 of 11 (36.4%) Ewing sarcoma tumor cells with ≥ 50% to <90% (+++, n=3) or ≥ 10% to <50% (++, n=1). In contrast, none of 6 Ewing-like sarcoma tumor cells expressed PD-1.Conclusion: In this study, PD-L1 expression was not observed in any of Ewing and Ewing-like sarcoma tumor cells. PD-1 was overexpressed in a subset of Ewing sarcoma, whereas not in Ewing-like sarcoma.

Keywords:

Programmed cell death-1; Ewing sarcoma; Ewing-like sarcoma

Cite the Article:

Tamura A, Yoshida M, Yamamoto N, Nino N, Ichikawa T, Nakatani N, et al. Robust Programmed Cell Death-1 Expression in a Subset of Ewing Sarcoma in Contrast to Ewing-like Sarcoma. Clin Oncol. 2019; 4: 1586.