In 2002, a study of germline (MEN2-related) and sporadic pheochromocytomas described the presence of the same 3 RET splice variants identified in the MTC cell line in pheochromocytomas (RET 2/4, RET 2/5 and RET 2/6) (Le Hir et al., 2002). Here, RET is linked to hereditary pheochromocytoma-paraganglioma.