MTOR and hereditary pheochromocytoma-paraganglioma: We were previously able to demonstrate synergistic effects of the targeted combination therapy using the specific phosphatidylinositol-3-kinase α inhibitor BYL719 together with the mammalian target of rapamycin inhibitor everolimus on pheochromocytoma cell spheroids and primary cultures of human pheochromocytomas [28].