By Cary J. Buresh, M.D.,
Director of Immunohistochemistry
Not long ago, we read about an immunohistochemical marker that was reported to have utility in the recognition of melanomas and peripheral nerve sheath tumors.
A neural crest transcription factor, Sox10 is required for maturation and maintenance of melanocytes and Schwann cells. Not surprising then, Sox10 shows strong nuclear reactivity in all Schwannomas and neurofibromas. It also stains the Schwann cell component of perineuriomas and normal peripheral nerves, and it reacts with ~50% of malignant peripheral nerve sheath tumors.
Other neoplasms that express nuclear Sox10 include granular cell tumor (a neoplasm of uncertain histogenesis, but currently thought to be of neural derivation and probably of Schwann cell origin), and it stains the nuclei of sustentacular cells in paragangliomas and pheochromocytomas.
Sox10 also marks normal myoepithelial cells of salivary gland and bronchial and mammary ducts and lobules, and it stains the myoepithelial component of salivary gland neoplasms such as myoepithelioma or pleomorphic adenoma.
Sox10 labels both benign melanocytes (nevus cells) and the vast majority of melanomas. In the detection of the latter, Sox10 has a sensitivity of 97% with a higher specificity than S100 protein. Some have also reported using Sox10 for the detection of lymph node metastasis in patients with melanoma undergoing sentinel lymph node biopsy. In that situation, the strong reactivity with S100 in normal lymph node dendritic cells can be avoided. We have also observed nuclear reactivity with Sox10 in clear cell sarcoma (melanoma of soft parts), a tumor which can show little, if any, melanocytic differentiation.
Finally, although I have not personally used Sox10 for this purpose, some authors have reported reactivity in astrocytomas, oligodendrogliomas, and medulloblastomas.
In summary, Sox10 is a superb nuclear marker of melanocytic lesions (with slightly higher sensitivity than S100 for the detection of melanoma), and it is also an excellent marker of Schwann cells and myoepithelial cells in a variety of tumors. It is clearly superior to S100 for the study of sentinel lymph nodes in patients with melanoma because it does not stain Langerhans cells and dendritic cells that are numerous in many lymph nodes. We have been using Sox10 with great success at ProPath for over a year, and we think that this antibody is underutilized. Sox10 is now available at ProPath.
References:
Nonaka D, Chiriboga L, Rubin BP. Sox10: A Pan-Schwannian and Melanocytic Marker. The American Journal of Surgical Pathology 32(9):1291-1298, 2008.
Blochin E, Nonaka D. Diagnostic Value of Sox10 Immunohistochemical staining for the Detection of Metastatic Melanoma in-Sentinel Lymph Nodes. Histopathology 55(5):626-628, 2009.
Date of last revision: July 2010.