Endocrine Abstracts

JOINT3367

Background: MicroRNAs (miRNAs) are small non-coding RNA molecules involved in the post-transcriptional regulation of gene expression. Pituitary adenomas (PA) are the second most common intracranial neoplasm, with invasive adenomas, defined as the tumor invading surrounding structures and the focal or extensive bones, acounting for 22%– 55% of PA cases. As circulating miRNAs are stable in human body fluids, the study aimed to analyze miR 16-5p, miR 143-3p and miR 423-5p expression in serum of patients with invasive non-functioning pituitary adenomas (NFPA) and prolactinomas, as candidates for non-invasive biomarkers.

Material and Methods: That was a prospective study with consecutive enrollment. The study included 62 Patients with NFPA and 19 Patients with macroprolactinoma qualified for transsphenoidal surgical resection. Clinical history, laboratory and imaging results, and endocrine tests were recorded. Peripheral blood was collected. MicroRNAs, without the high molecular RNA fraction, were isolated from serum samples using the double-column system for miRNA and RNA isolation, according to the manufacturer’s protocol (A&A Biotechnology, Gdansk, Poland). The qPCR was performed using SolisFAST Probe qPCR Mix with UNG (Solis Biodyne, Tartu, Estonia). The expression levels of hsa-miR-191-5p, hsa-miR-16-5p, hsa-miR-143-3p, and hsa-miR-423-3p were determined using TaqMan MicroRNA Assays (Thermo Fisher Scientific, Waltham, MA, USA). hsa-miR-191-5p served as a reference miRNA. Relative expression level analysis was performed using the same software by comparing the expression level of the genes of interest with that of the reference gene. The control group (CG) consisted of 26 healthy volunteers. The statistical analysis was performed with MedCalc, with significance level set as P <0.05.

Results: The analysis involved 62 patients with NFPA (47% males) and 19 patients with macroprolactinoma (74% males). The total concentration of microRNA was significantly lower in NFPA than in the CG (P = 0.0419). We did not observe that for prolactinoma. No correlation between selected miRNAs and tumor type was found, miR-143-3p (P = 0.4610), miR-16-5p (P = 0.8767), miR-423-5p (P = 0.1459). The expression of miRNA also did not correlate with invasiveness (cavernous or sphenoid sinus invasion, compression of the optic chiasm). We observed significantly lower levels of FSH, LH, estardiol, testosterone and fT4 in NFPA and prolactinomas than in control group (P <0.05). IGF-1 and fT3 were significantly lower in NFPA than CG (P = 0.024, P = 0.0067, respectively).

Conclusions: Although the total expression of microRNA was significantly lower in NFPA, miR 16-5p, miR 143-3p and miR 423-5p are not useful as non-invasive biomarkers in patients with invasive non-functioning pituitary adenomas and prolactinomas.