Integrin b4 expression in peripheral-nerve tumors

The alpha 6 beta 4 integrin complex is expressed in epithelial, endothelial and nerve cells. We analyzed the immunohistochemical expression of the beta 4 subunit in normal peripheral nerves, in neurofibromas associated with type 1 neurofibromatosis and in sporadic neurofibrosarcomas. In normal peripheral nerves (4 samples), the beta 4 integrin was diffusely expressed at the level of the perinevrium and at the interface between axons and Schwann cells. In neurofibromas (6 cases), beta 4 was undetectable or markedly decreased relative to normal peripheral nerves. Neurofibrosarcomas (3 cases) were immunohistochemically negative for beta 4 expression. These observations suggest that a down-regulation of the alpha 6 beta 4 integrin is associated with the neoplastic progression of peripheral nerve tumors.