CTLA4 and synovial sarcoma: The anti-CTLA4 agent ipilimumab is approved for melanoma immunotherapy and currently in clinical trials for patients with a variety of other solid tumors including various sarcoma subtypes (NCT00556881), although a trial with another anti-CTLA4 monoclonal antibody, MDX-010, in synovial sarcoma patients (NCT00140855) was closed due to poor accrual.