RET and thyroid cancer: More recently, the selective RET kinase inhibitors selpercatinib and pralsetinib have been approved for use in patients with RET mutations in these malignancies.85,86,167 In a phase 1 to 2 study of 162 patients with RET-mutant medullary thyroid or RET fusion-positive thyroid cancer treated with selpercatinib, 43% developed any grade hypertension.