Diagnosis of Invasive Nonfunctional Pituitary Adenomas by Serum Extracellular Vesicles

The invasiveness evaluation of nonfunctional pituitary adenoma (NFPAs) is crucial for the prediction of the malignant potential and for making surgical plans of NFPAs. Current invasiveness evaluation of NFPAs is based on neuroimaging, which can hardly predict the invasive potential and dynamically monitor disease progress. Here we used microbead-assisted flow cytometry to detect and analyze the serum extracellular vesicles (EVs) from 30 NFPAs patients (15 invasive and 15 noninvasive). Lower expressions of folate receptor 1 (FOLR1) and epithelial cell adhesion molecule (EpCAM) were found in serum EVs from the invasive NFPAs patients compared to the noninvasive ones [area under the curve (AUC) of 0.94 for FOLR1 and 0.88 for EpCAM]. Meanwhile, increased mRNA expression of vimentin and N-cadherin, two mesenchymal markers, was found in serum EVs from the invasive NFPAs patients compared to the noninvasive ones. Consistent results were observed in the tumor tissue that invasive NFPAs have lower expression of the epithelial markers while higher expression of the mesenchymal markers. These results suggested the possible role of epithelial-mesenchymal transition (EMT) in the invasiveness of NFPAs. Pituitary tumor transforming gene 1 (PTTG1) mRNA in serum EVs was also found to be an indicator for invasive NFPAs and is related with EMT. These results provide a method for the blood-based diagnosis and invasiveness evaluation of NFPAs and would be beneficial to the diagnosis, prognosis prediction, and surgical risk evaluation of NFPAs.