7 - Stem Cell Markers in Pituitary Adenomas

Abstract

This chapter discusses stem cell markers in pituitary adenomas. Stem cells are the source of progenitor cells for tissue, and they present several capacities: self-renewal, proliferation, and differentiation toward adult pituitary cells. These cells have long-term self-renewal capacity and asymmetric division, giving rise to one stem cell and one progenitor cell with shorter self-renewal capacity. Stem cells can be involved not only in normal pituitary turnover and adaptation, but also in pituitary adenoma pathogenesis, being a source of a proliferation if they are subject to oncogenetic mutation. In the adult pituitary, multipotent or oligopotent stem cells can be identified in a small proportion, being represented by the population of FSCs, follicular cells (FCs), marginal cells (MCs), and cells with mesenchymal phenotype in the side population (SP). Markers of the stem cells in the pituitary gland are dependent on the group of cells. The FSC markers are angiotensin-converting enzyme (ACE), stem cells antigen 1 (Sca-1), fibronectin, nestin, and SOX-2. Follicular cells have no markers, while MC markers include ACE, Sca-1, nestin, and SOX-2 as cell markers.