The concurrent assessment of relevant pharmacodynamic modulation in study patient tumor tissues was beyond the scope of the current study; however, future pharmacodynamic studies in dogs receiving sorafenib would provide important confirmatory data that serum concentrations of sorafenib are associated with relevant therapeutic target (e.g., Raf kinases, VEGFR and PDGFR) modulation in vivo. The gene discussed is PDGFRB; the disease is neoplasm.