Integrin β4 expression in peripheral nerve tumors

The α6β4 integrin complex is expressed in epithelial, endothelial and nerve cells. We analyzed the immunohistochemical expression of the β4 subunit in normal peripheral nerves, in neurofibromas associated with type 1 neurofibromatosis and in sporadic neurofibrosarcomas. In normal peripheral nerves (4 samples), the β4 integrin was diffusely expressed at the level of the perineurium and at the interface between axons and Schwann cells. In neurofibromas (6 cases), β4 was undetectable or markedly decreased relative to normal peripheral nerves. Neurofibrosarcomas (3 cases) were immunohistochemically negative for β4 expression. These observations suggest that a down-regulation of the α6β4 integrin is associated with the neoplastic progression of peripheral nerve tumors.