BIOLOGY OF VESTIBULAR SCHWANNOMA: THE ROLE OF PTEN AND MICRORNA-21

Vestibular schwannomas (VS) are benign slow growing tumors, arising from the VIII cranial nerve, generally involving the inferior vestibular nerve. This tumor could be part of a systemic disease called Neurofibromatosis type 2 (NF2), in which the tumors are bilateral and more aggressive. The identification of prognostic factor should help the otoneurologist in selecting a proper management. Whereas radiological features and presenting symptoms did not result good prognostic factor or predictor element of tumor development, molecular elements, as well as microRNA, could be useful to act as predictive factors of biological behavior of VS in time. It is clear that miR-21 plays a significant role in the regulation of multiple pathways controlling cell proliferation in many cancers, and this attribute makes it a very attractive target for the development of new therapies. Future experiments aimed at manipulating miR-21 expression in schwannoma models will allow us to test the relative importance of miR-21 on VS growth in vivo. The close relationship between growth and miR-21 expression lead to considerate such molecular factor as a prognostic indicator, after further verifications, to select patients manageable with observation or with an early hearing preservation surgery.