RET and differentiated thyroid carcinoma: Although previous studies suggested that cabozantinib treatment exhibited greater inhibitory activity relative to vandetanib treatment in cells harboring the RET/papillary thyroid carcinoma (PTC) fusion gene, which is also known as CCDC6-RET, [41, 42] and preliminary data from Drilon et al. [13] revealed partial responses to cabozantinib treatment in a prospective phase II trial involving patients with RET-fusion-positive NSCLC, cabozantinib appears to be an ineffective agent for cells expressing KIAA1217-RET fusion proteins (Supplementary Figure S4).