STXBP1 and pheochromocytoma: For example, syntaxin binding protein 1 (STXBP1, commonly named Munc18-1) is overexpressed in pheochromocytoma (Houy et al., 2022), whereas expression level of the GTPases Rab3a-c or Rab27a-b and granuphilin (sytl4) is modified in pheochromocytoma, medullary thyroid carcinoma and in somatotroph or corticotroph pituitary tumor (Table 1), (Zhan et al., 2018; Houy et al., 2022; Zhang et al., 2022; Chen et al., 2023).