EPAS1 and pheochromocytoma: In addition, EPAS1 DNA number changes (ratio of expression) in phaeochromocytomas/paragangliomas were significantly (p < 0.01) higher when compared to that of non-neoplastic adrenal tissues (1.486 ± 0.011 versus 1.186 ± 0.015) (Figure 3A).