RET and neoplasm: Apart from VEGFR, inhibition of other signaling pathways like platelet-derived growth factor receptor (PDGFR), stem cell factor receptor (KIT), FMS-like tyrosine kinase 3 (FLT3), colony-stimulating factor 1 receptor (CSF-1R), and rearranged during transfection (RET) may have resulted in the supplementary effect on tumor proliferation, angiogenesis and lymphangiogenesis [22, 23].