RET and medullary thyroid gland carcinoma: In this study, vandetanib, a multi-targeted TKI that has been clinically proven to be effective in RET-related cancers including MTC and NSCLC, suppressed the Ras/Raf/MEK/ERK and PI3K/AKT pathways by mainly inhibiting the tyrosine kinase activity of RET, leading to a decrease in catecholamine synthesis in PC12 cells.