Endocrine Abstracts

Objectives: To study the effect of epithelial-to-mesenchymal transition (EMT) on hormone expression in gonadotroph non-functioning pituitary neuroendocrine tumours (NF-PitNET).

Background: Gonadotroph PitNETs can express FSH and LH or be hormone negative, however they rarely secrete hormones. During tumour development, epithelial cells develop a mesenchymal phenotype. This process is characterised by decreased membranous E-cadherin and translocation of E-cadherin to the nucleus. Further, oestrogen receptors (ER) regulate both E-cadherin and FSH expression and secretion. Whether the hormone status of patients with gonadotroph PitNETs are regulated by EMT and oestrogen receptors is uncertain.

Methods: Retrospective study of 105 gonadotroph PitNETs. Immunohistochemical analyses and real-time-qPCR for FSH, LH, E-Cadherin and ERα were performed. Blood samples, clinical data and radiological findings were analysed.

Results: NF-PitNET with high FSH expression had decreased immunohistochemical staining for membranous E-cadherin (r = −0.384; P < 0.0001) and increased staining for nuclear E-cadherin (P < 0.0001). Further, high FSH expression was associated with increased ERα staining (r = 0.357; p = 0.0002) and mRNA (r = 0.331, P = 0.0039). Circulating levels of P-FSH correlated with FSH staining in NF-PitNET (r = 0.360; P = 0.0025). Tumour size and invasiveness was not related to FSH staining, E-cadherin or oestrogen receptor. LH expression in tumours were not associated with E-cadherin or ERα. In gonadotroph PitNETs, FSH staining is associated with decreased membranous E-cadherin and nuclear translocation of E-cadherin. FSH correlates with expression of oestrogen receptors and circulating P-FSH. Further studies are needed to understand the mechanisms behind these findings.