SDHB and hereditary pheochromocytoma-paraganglioma: Taken together, these observations indicate that the expression of EMT, hedgehog, and hypoxia pathways is strongly linked to the SDH complex deficiency, a feature shared with pheochromocytoma/paraganglioma, which could explain and support clinically relevant differences with other GIST subgroups, such as for the metastatic behavior.