Endocrine Abstracts

Introduction: MicroRNAs are short, single-stranded, protein non-coding RNA molecules which can be secreted into the circulation by mammalian cells. Their altered expression pattern has been described in many different physiological and pathological conditions. In the extracellular compartments they are encapsulated within vesicles, associated to proteins or apoptotic bodies. Due to their stability they are suggested as promising circulating biomarkers. Regarding pituitary adenoma several studies have been published describing the different expression pattern of miRNAs and their role in adenomagenesis on tissue level, but only a few publications investigated circulating miRNAs.

Aim: To identify pituitary tissue-specific miRNAs in circulation comparing tissue and blood miRNA profiles reported in literature.

Methods: Data mining of available serum or plasma miRNAs detected in patients with pituitary adenomas. Reevaluation of expression data and correlation with tumor biology.

Results: Overall, a global downregulation of miRNA expression was reported in plasma samples obtained from patients with pituitary adenoma compared to healthy controls. Pituitary adenoma tissue-specific miRNAs have low abundance in plasma, minimizing their role as biomarkers. To date, only miR-143-3p was reported as plasma maker for non-functioning adenomas which level decreased following surgery.

Discussion: Circulating miRNAs in pituitary adenoma would help patient care especially in non-functioning adenoma as minimally invasive biomarkers of tumor recurrence and progression. However, technical difficulties may challenge the clinical use of miRNAs as potential biomarker and the application of standardized protocols could help their clinical utility. MiR-143-3p may predict tumor recurrence but it needs further investigation.