Patients with Ewing sarcoma tested for germline mutations in PTPRD and outcomes with IGF-1R-based therapy...Among these seven patients, five had wild-type PTPRD and two had PTPRD germline mutations: T781A and R995C. The tumor tissues from these two patients were not available for testing. A second patient with a PTPRD mutation (Patient 5, Table ​Table1)1) also attained a CR on IGF-1R inhibitor-based therapy.