Each group should be represented by one or two reference centers depending on the size of the country. These centers:

• are among the largest accruers in sarcoma clinical trials worldwide
• have a high level of knowledge in the disease, and
• will concentrate their expertise on molecular diagnosis and accrual as rare as it may be.

Accrual of patients with selected histological types will be helped substantially by the fact that they will represent a national collaborative group.