Current Status of Proteomics in Ewing's Sarcoma.

Ewing's sarcoma is an extremely rare mesenchymal malignancy of the bone, which predominantly occurs in children and young adolescents. Ewing's sarcoma is characterized by chromosomal translocations resulting in the formation of chimeric fusions between the EWS gene and transcription factors of the ETS family, such as EWS-FLI-1. The clinical outcome of Ewing's sarcoma remains poor, and novel therapeutic approaches are required. Proteomic analyses have been applied to identify the functions of the fusion gene product, and a novel mechanism of EWS-FLI-1 turnover has been proposed. Furthermore, proteomics has revealed the regulation of IL-6 secretion by EWS-FLI-1, which may promote malignant behavior in tumor cells. In addition, proteomic approaches have been used to assess the effects of unique genes and drugs on Ewing's sarcoma and to determine specific biomarker candidates for the prediction of drug resistance and recurrence. By identifying the proteins relevant to the molecular backgrounds of clinical characters of Ewing's sarcoma, we can understand the biology of Ewing's sarcoma and develop clinical applications. Fundamental research systems such as tumor cell and tissue biobanks and databases are required to make effective use of the limited clinical materials and promote research into Ewing's sarcoma.