The overall response rate to sunitinib for metastatic PPGLs is generally low; however, a small series suggests that SDHx-mutated tumors may respond to anti-angiogenic TKIs, and RET-altered pheochromocytomas have responded to selective RET inhibitors (e.g., selpercatinib), although robust predictive evidence for greater benefit with multi-target TKIs by genotype remains limited [63]. This evidence concerns the gene RET and hereditary pheochromocytoma-paraganglioma.