PDGFRB and neoplasm: To further validate our mECK36 animal model as a potential preclinical model to test PDFGRA-targeted therapies to KS, we tested the efficacy of Imatinib Mesylate (Gleevec), a FDA-approved Bcr-Abl, c-kit, and PDGFR inhibitor that showed tumor responses in Phase I and II AIDS-KS clinical trials [33, 34], in the mECK36 tumorigenicity model.