CAT and neoplasm: However due to the high heterogeneity of tumors for CAT content and secretion (Fig 2A and 2B), PHEO were further subdivided into two groups; PHEO were considered as noradrenergic (NorAd PHEO) when the E concentration in tumor tissue was below 10% of total CAT (NE+E), and tumors with E concentration above 10% of total CAT were termed as mixed PHEO (Table 1) as previously published [12].