MUC16 and pheochromocytoma: It has been reported that the typical tumor marker CA125 encoded by the MUC16 gene played a vital role in regulating tumor cell metastasis (26), and succinate dehydrogenase (SDH) complex subunits mutations were reported highly associated with tumor cells metastases in pheochromocytoma and paraganglioma and other malignancies (27, 28).