Serums miR-24-3p and miR-1301-3p as Potential Biomarkers in MEN1 Syndrome

Multiple endocrine neoplasia type 1 (MEN1) is a rare hereditary tumor syndrome caused by inactivating mutations of the MEN1 gene and characterized by the occurrence of multiple endocrine tumors within a single patient (i.e., parathyroid, pituitary, and pancreatic neuroendocrine tumors (NETs)). However, the lack of a genotype-phenotype correlation does not allow individual disease evolution to be foreseen. Epigenetic factors, such as microRNAs, are suspected to contribute to MEN1 tumorigenesis, presumably explaining the lack of genotype-phenotype association. Our previous studies indicated miR-24-3p, miR-1301-3p, miR-664a-3p, and miR-4258 as potentially involved in MEN1 parathyroid tumorigenesis. In this study, we examined the expression of two circulating microRNAs (c-miRNAs), miR-24-3p and miR-1301-3p, in the serum of MEN1 patients. c-miRNAs were evaluated by RT-qPCR in serum collected from 25 MEN1 patients and 25 age- and gender-matched healthy volunteers (HCs). Receiver operating characteristic (ROC) curves were constructed to determine miRNA sensitivity and specificity. RT-PCR analysis revealed that expression levels of circulating miR-1301-3p were significantly downregulated, while those of miR-24-3p were significantly upregulated in the serum of MEN1 patients compared to HCs. Additionally, ROC analysis exhibited a good diagnostic power for both miRNAs (area under the ROC curve (AUC) values: 0.7356 and 0.7928 for miR-1301-3p and miR-24-3p, respectively) in distinguishing MEN1 patients from matched HCs. These preliminary data suggest circulating miR-1301-3p and miR-24-3p as potential non-invasive diagnostic biomarkers for MEN1 syndrome, regardless of different clinical phenotypes and MEN1 mutation types.