Expression of CCL21 in Ewing sarcoma shows an inverse correlation with metastases and is a candidate target for immunotherapy.

Laurens G L Sand,Dagmar Berghuis,Karoly Szuhai,Pancras C W Hogendoorn

doi:10.1007/s00262-016-1862-1

Laurens G L Sand, Dagmar Berghuis + Show 2 more

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https://doi.org/10.1007/s00262-016-1862-1

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Abstract

Ewing sarcoma is an aggressive neoplasm predominantly occurring in adolescents and has a poor prognosis when metastasized. For patients with metastatic disease in particular, immunotherapy has been proposed as possible beneficial additive therapy. CCL21 activation-based immunotherapy was successful in preclinical studies in other tumor types; therefore, we investigated CCL21 expression in Ewing sarcoma as potential target for immunotherapy. The CCL21 RNA expression was determined in 21 Ewing sarcoma cell lines and 18 primary therapy-naive Ewing sarcoma samples. In the tumor samples, this was correlated with the number and CD4+/CD8+ ratio of infiltrating T cells and clinical parameters. Higher RNA expression levels of CCL21 significantly correlated with a lower CD4+/CD8+ T cell ratio (P = 0.009), good chemotherapeutic response (P = 0.01) and improved outcome (P < 0.001). In patients with metastases, CCL21 expression was significantly lower than in patients without (P < 0.0005). CCL21 expression was significantly higher in Ewing sarcoma tissue samples compared to cell lines (P < 0.01), implying the involvement of a stromal factor. Protein expression analysis of CCL21 and its receptor CCR7 in 24 therapy-naïve tumors showed that there was no expression in all bar one Ewing sarcoma cells. In conclusion, CCL21 is expressed in clinical Ewing sarcoma samples by nontumor-infiltrating immune cells. The observed positive correlation with survival implies that CCL21 might be a potential prognostic marker for Ewing sarcoma and marks the potential of CCL21 immunotherapy for use in Ewing sarcoma.Electronic supplementary materialThe online version of this article (doi:10.1007/s00262-016-1862-1) contains supplementary material, which is available to authorized users.

Highlights

Ewing sarcoma (EWS) is the third most common primary bone sarcoma which predominantly occurs in children and adolescents [1]
RNA expression of CCL21 was analyzed in 18 primary therapy-naïve tumor samples, and the expression levels were correlated with the immunohistochemical staining of the CD4+- and CD8+-infiltrating T cells in eight tissue samples for which sufficient formalin-fixed paraffin-embedded (FFPE) material was still available (Supplementary Table S2)
Since a high-CD8+ T cells infiltration was associated in Ewing sarcoma with a better outcome, we correlated CCL21 RNA expression levels in therapy-naïve tumor samples with development of metastases, survival and chemotherapeutic response

Summary

Introduction

Ewing sarcoma (EWS) is the third most common primary bone sarcoma which predominantly occurs in children and adolescents [1]. It is characterized by aggressive/destructive local growth and has a high-grade malignant behavior, with (micro-) metastases at the time of presentation being common. Patients with metastases or recurrent disease have a poor outcome with 15–30 % long-term survival [2, 3]. After the initial introduction of multimodal chemotherapy, no further improvement in survival of these patients has been accomplished, and besides the classical parameters such as tumor site, resectability, response to chemotherapy and size, no prognostic markers are in clinical use for decision making. Immunotherapy in Ewing sarcoma has been shown to have a promising potential role in vitro and is being tested in two clinical trials by administrating donor NK-cells (NCT01287104, NCT02100891) [7, 8, 10]

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