Vestibular schwannomas, also known as
acoustic neuromas, are benign
tumors, which originate from myelin-forming Schwann cells. They develop in the vestibular branch of the eighth cranial nerve in the internal auditory canal or cerebellopontine angle. The
clinical progression of the condition involves slow and progressive growth, eventually resulting in brainstem compression. The objective of the present study was to investigate the expression level and the localization of the pro-inflammatory
cytokines, transforming growth factor-β1 (TGF-β1)
interleukin (IL)-1β,
IL-6 and
tumor necrosis factor-α (TNF-α), as well as the adhesion molecules, intracellular adhesion molecule-1 and
vascular endothelial growth factor (
VEGF), in order to determine whether these factors are involved in the transformation and development of human
vestibular schwannoma. The present study investigated whether changes in
inflammation are involved in
tumor growth and if so, the mechanisms underlying this process. The results of the current study demonstrated that pro-inflammatory
cytokines, including TGF-β1, IL-1β and
IL-6 exhibited increased expression in human
vestibular schwannoma tissue compared with normal vestibular nerve samples. TNF-α was weakly expressed in Schwann cells, confirming that a lower level of this
cytokine is involved in the proliferation of Schwann cells. Neoplastic Schwann cells produce pro-inflammatory
cytokines that may act in an autocrine manner, stimulating cellular proliferation. In addition, the increased expression of
VEGF in
vestibular schwannoma compared with that in normal vestibular nerve tissue, suggests that this factor may induce neoplastic growth via the promotion of angiogenesis. The present findings suggest that
inflammation may promote angiogenesis and consequently contribute to
tumor progression. In conclusion, the results of the present study indicated that
VEGF and pro-inflammatory
cytokines may be potential therapeutic targets in
vestibular schwannoma. Further studies are necessary to confirm the involvement of these factors in the growth of
neoplasms and to develop inhibitors of pro-inflammatory
cytokines as a potential treatment option in the future.