Update of Pituitary Tumor Pathogenesis

Pituitary tumors are mostly sporadic and benign neoplasias and only less than 5% of them have a hereditary background. Despite considerable progress, the pathogenesis of pituitary tumors is still insufficiently understood. Materials & Methods: Literature databases have been screened for papers presenting new findings about tumorigenesis and progression of pituitary tumors. The most important new developments in pituitary tumor pathogenesis research will be summarized and discussed. Results: For most pituitary adenoma types hardly any new findings explaining the genesis of these tumors have been reported during the last 4 years. However, in corticotroph pituitary tumors,recurrent mutations of the deubiquitinases USP8 and USP48 have exclusively been found in about 40% and 10% of patients with Cushing’s disease, respectively. Moreover, putative mechanisms explaining the consequences of these mutations in corticotroph adenomas have been suggested and will be discussed. Concerning pituitary tumor progression, proteomic approaches have led to the detection of several factors, which seem to play a role in epithelial mesenchymal transition (EMT), a process wich is critically involved in the transformation of pituitary tumors from a benign to a aggressive, invasively growing phenotype. Conclusion: Current new findings have further elucidated the pathogenesis, pathophysiology and progression of pituitary tumors but still a lot of work needs to be done to better understand the background of pituitary tumor formation.