TH and neoplasm: TH and PNMT genes were down regulated in PGL compared with mixed PHEO by 3.5 and 41.7 fold respectively (P = 0.03 and P = <0.001) while no differences were recorded for DBH (Fig 5A) As observed for E and NE concentration in tumor tissue, there was no significant difference between CAT synthesis genes expression for PGL and NorAd PHEO (Fig 5B).