EXPRESSION OF C-JUN & SOX-2 IN HUMAN SCHWANNOMAS AND TRAUMATIC NEUROMAS

INTRODUCTION: Schwann cells myelinate axons of the peripheral nervous system. This process of myelination is regulated by various transcription factors. c-Jun and Sox-2 are negative regulators of myelination and control Schwann cell demyelination/ de-differentiation. Schwannoma cells are in a de-differentiated state with an ability to proliferate and avoid cell death. In vitro experiments in our lab have shown that c-Jun and Sox-2 are extensively co-regulated and that some of the inhibitory effects of c-Jun on myelination may be channelled through Sox-2. In this study, we look at the expression of these two negative regulators of myelination (c-Jun, Sox-2) in human schwannoma and traumatic neuroma. METHOD: 6 cases of schwannoma, 2 cases of traumatic neuroma and 1 control peripheral nerve were selected from the archives of the Neuropathology Department. The tissue was consented for use in research and had Ethics Committee approval. Immunohistochemistry was performed on 4 µm sections using antibodies to c-Jun and Sox-2. Western blot analysis was also carried out using anti-c-Jun antibodies. RESULTS: The schwannoma cells showed strong nuclear labelling with c-Jun and Sox-2. The c-Jun staining on traumatic neuroma reveals nuclear labelling. The Sox-2 staining was patchy and cytoplasmic in a neuroma. The control nerve did not stain with c-Jun and Sox-2 antibodies. Western blot of 3 schwannoma cases displayed increased c-Jun expression compared to normal tissues. CONCLUSION: Our data shows evidence of increased expression of c-Jun and Sox-2 in schwannomas compared to traumatic neuroma and normal peripheral nerve.