SDHB and pheochromocytoma: Succinate accumulation, due to loss-of-function mutations in genes encoding the subunits of SDH [90,126,127,128,129,130], leads to the development of various types of tumors, such as paragangliomas and pheochromocytomas [9,29,126,130,131,132,133,134], gastrointestinal stromal tumors (GISTs) [127,129,132,135,136,137,138,139], renal carcinomas [131,132,140,141], pituitary tumors [131,142,143] and others [127,131,132,134,144].