International Journal of Molecular Sciences Review Multiple Endocrine Neoplasia Type 1: The Potential Role of microRNAs in the Management of the Syndrome Simone Donati 1, Simone Ciuffi 1 , Francesca Marini 1, Gaia Palmini 1 , Francesca Miglietta 1, Cinzia Aurilia 1 and Maria Luisa Brandi 1,2,3,* 1 Department of Experimental and Clinical Biomedical Sciences “Mario Serio”, University of Study of Florence, Viale Pieraccini 6, 50139 Florence, Italy;
[email protected] (S.D.); simone.ciuffi@unifi.it (S.C.); francesca.marini@unifi.it (F.M.); gaia.palmini@unifi.it (G.P.);
[email protected] (F.M.);
[email protected] (C.A.) 2 Unit of Bone and Mineral Diseases, University Hospital of Florence, Largo Palagi 1, 50139 Florence, Italy 3 Fondazione Italiana Ricerca Sulle Malattie Dell’Osso (FIRMO Onlus), 50141 Florence, Italy * Correspondence: marialuisa.brandi@unifi.it; Tel.: +39-055-7946304 Received: 24 September 2020; Accepted: 12 October 2020; Published: 14 October 2020 Abstract: Multiple endocrine neoplasia type 1 (MEN1) is a rare inherited tumor syndrome, characterized by the development of multiple neuroendocrine tumors (NETs) in a single patient. Major manifestations include primary hyperparathyroidism, gastro-entero-pancreatic neuroendocrine tumors, and pituitary adenomas. In addition to these main NETs, various combinations of more than 20 endocrine and non-endocrine tumors have been described in MEN1 patients. Despite advances in diagnostic techniques and treatment options, which are generally similar to those of sporadic tumors, patients with MEN1 have a poor life expectancy, and the need for targeted therapies is strongly felt. MEN1 is caused by germline heterozygous inactivating mutations of the MEN1 gene, which encodes menin, a tumor suppressor protein.