PDGFRB and neoplasm: Given the effects of combined treatment with imatinib and rapamycin on cell proliferation as well as the ability of this combination to reduce the levels of phospho-PDGFRβ and phosphor-Akt, we assessed the effects of this combination on tsc2ang1 tumorigenesis in vivo. While each drug individually reduced the size of tumors formed compared to vehicle control, combined treatment with imatinib and rapamycin resulted in a nearly complete abrogation of tumor growth (97% decrease in tumor volume compared with control, p < 0.0001) (Figure 4).