SDHB and hereditary pheochromocytoma-paraganglioma: Gastrointestinal stoma tumors (GISTs) harboring mutant SDH have genomic DNA methylation an order of a magnitude greater than c-Kit-mutated GISTs.90 Genomic hypermethylation was also observed in patients with SDH-mutant hereditary paraganglioma and pheochromocytoma.