Markers of function and proliferation in non-invasive and invasive bi- andplurihormonal adenomas of patients with acromegaly: An immunohistochemicalstudy

Twenty-seven plurihormonal and 21 growth hormone prolactin - (GH- PRL-) mix ed cell adenomas obtained from patients with acromegaly undergoing transnas al-transsphenoidal surgery were investigated immunohistochemically for expr ession of Epidermal Growth Factor (EGF), Transforming Growth Factor alpha T GF(alpha) Insulin-like Growth Factor-1 (IGF-1), Estrogen Recptor-Related Pr otein (ERRP), Multidrug Resistance Marker (MDRM), Protein Kinase C (PKC), G (s)alpha Cathepsin D and p53. Five plurihormonal adenomas grew invasively. The panel of markers used in this study represents a selection of functiona l and proliferative markers thought to be associated with the function and development of pituitary adenomas. Our results imply that the growth factor s (EGF TGF alpha, IGF-1), the cell signalling protein G(s)alpha and the MDR M are expressed by both types of pituitary adenomas in a similar pattern. N on-invasive GH-PRL-mixed cell adenomas showed an increased expression of IG F-1, TGF alpha and MDRM compared to non-invasive plurihormonal adenomas. No factor was found which would reliably distinguish between invasive and non -invasive adenomas. We failed to confirm the findings of others that p53 an d cathepsin D might be indicators of tumor aggressiveness. A participation of ERRP and PKC in the development of bi-and plurihormonal adenomas with ac romegaly appears unlikely, as the immunostains were all negative.