Advancing preclinical biology for Ewing Sarcoma: an international effort.

Ewing sarcoma (EwS) is an aggressive bone and soft tissue cancer affecting adolescents and young adults. In vitro and in vivo models of EwS have been instrumental in advancing our understanding of EwS biology and essential in evaluating potential therapies, particularly for metastatic or relapsed disease where effective treatment options remain limited. Through an international collaborative effort between the Children's Oncology Group (COG) Bone Tumor Committee and the Euro Ewing Consortium (EEC), we review the current landscape of preclinical modeling used in EwS research encompassing both in vitro (cell lines and tumor organoids) and in vivo (mouse and non-mammalian xenografts) model systems. We discuss factors that can influence experimental results, provide testing considerations for both in vitro and in vivo studies, and descriptions of existing preclinical data repositories. We highlight current needs in EwS modeling and the importance of enhanced international cooperative research and patient advocacy efforts which will be critical in expanding our resources of biologically-relevant EwS models to enable translation of preclinical findings into effective therapeutic strategies for EwS patients.