Sorafenib has also demonstrated activity in desmoid tumors, which are fibroblastic neoplasms that arise from musculoaponeurotic stromal elements.73 Imatinib, a KIT/PDGFR/BCR-ABL TKI that is used as first-line therapy for patients with unresectable/metastatic GIST, was evaluated in 10 histological sarcoma subtypes, producing responses in 4 of 185 patients (2%).74 When SD (> 4 months) was included, the clinical benefit rate (CBR) was 15% overall, with the highest CBR noted in patients with liposarcomas and leiomyosarcomas. The gene discussed is PDGFRB; the disease is leiomyosarcoma.