PDGFRB and renal cell carcinoma: The levels of TIMP2 and TIE2 were decreased on cabozantinib; this is in line with the observed decrease in their levels in patients with renal cell carcinoma treated with the multi-VEGFR-PDGFR inhibitor regorafenib [31], demonstrating a consistent change in micro-environment-related and angiogenesis-related biomarkers on treatment with VEGFR TKI.