Localization of Epidermal Growth Factor (EGF) and Epidermal Growth Factor Receptor (EGFr) in Human Pituitary Adenomas and Nontumorous Pituitaries: An Immunocytochemical Study

Epidermal growth factor (EGF) and epidermal growth factor receptor (EGFr) were investigated by immunocytochemistry (ICH) in 57 human pituitary adenomas and 10 nontumorous autopsy pituitaries. EGF immunoreactivity was demonstrated in 24 adenomas (42%), representing 23 functioning tumors and 1 nonfunctioning tumor of oncocytic type, and in all nontumorous pituitaries. Among 40 tumors, EGFr was found positive in 15 functioning adenomas (37.5%), representing 50% of them. The presence of both EGF and EGFr was found mainly in corticotroph adenomas (60%) and less frequently in somatotroph and lactotroph adenomas (20%). ICH on serial sections with EGF or EGFr and adrenocorticotrophic hormone (ACTH) or S-100 protein revealed that EGF and EGFr are localized specifically in corticotrophs and EGFr in stellate cells of nontumorous adenohypophysis. These results confirm the presence of EGF and EGFr in human pituitary adenomas and nontumorous pituitaries and highlight their frequent occurrence in hormone-producing adenomas. Further work is required to explore the possibility that EGF and EGFr play a role in hormone production, release, and tumor progression.