RET and pheochromocytoma: Tumors adhering to the kinase cluster (approximately 50% of all PPGLs) are often pheochromocytomas with low metastatic potential, and this cluster contains tumors with either germline or somatic mutations in NF1, RET, Myc-associated factor X (MAX), Transmembrane Protein 127 (TMEM127), Kinesin Family Member 1B (KIF1B-β), and HRAS [29, 38, 41–44].