FGF2 and neoplasm: A possible molecule mediating this effect and worthy of future investigation is fibroblast growth factor 2 (FGF2), because FGF2 is a mitogen, its serum levels are significantly higher in women than men without VS, and sporadic VS that secrete high levels of FGF2 have previously been associated with better hearing than VS that secrete low levels of FGF2 irrespective of tumor size (34, 35).