Endocrine Abstracts

Introduction: Gonadotroph tumours (GT) are the most common subtype of silent pituitary neuroendocrine tumours. The diagnosis of this subtype of tumours is established after surgery. There are no reliable markers of aggressiveness to predict their clinical course and, moreover, immunohistochemistry (IHC) usually classifies GT as null cell tumours. The aim of the present study was to correlate molecular, immunohistochemical and biochemical gonadotropin expression, to quantify the gene expression of transcription factors of gonadotroph lineage and to correlate molecular data with demographic, clinical and radiological variables.

Material and Methods: 34 molecularly identified GT were selected from PitNET collection of the Biobank of the Alicante Health and Biomedical Research Institute. Demographic variables (age, gender), clinical variables (neurophthalmological manifestations, pituitary hormone deficiency, invasiveness of the cavernous sinus, maximum tumour diameter, re-intervention), biochemical variables (pre-surgical concentrations of FSH and LH), IHC variables (protein expression of FSH and LH) and molecular variables (expression of FSH, LH, gonadotroph lineage transcription factors (ESR1, SF1 and GATA2)) were studied.

Results: 13 patients (38.2%) were women and 21 (61.8%) men. The average age was 58.9 ± 15.4 years. Among neurophthalmological manifestations the most prevalent was the oculomotor manifestation (58.8%) followed by headache (38.2%). 24 tumours (70.6%) were invasive. GT showed higher expression of GATA2 gene (mean: 10.590 ± 9.309) compared with SF1 (mean: 0.619 ± 0.284) and ESR1 (mean: 0.225 ± 0.271). We observed a statistically significant correlation between gene and IHC expression of FSH (r = 0.380, P = 0.024). Protein expression of FSH correlated positively with pre-surgical concentrations of FSH (r = 0.45, P < 0.01). Tumour size correlated negatively with FSH gene expression (r = −0.44), P < 0.01). None of the aforementioned variables had a significant association with growth and aggressiveness (P > 0.05).

Conclusions: The positive correlation between pre-surgical levels of FSH and the IHC expression of FSH would allow anticipate the diagnosis of GT before surgery. The quantification of expression gonadotroph-lineage transcription factor genes could help diagnose these tumours.