The pattern of distribution of laminin in neurogenic tumors, granular cell tumors, and nevi of the oral mucosa.

Oral tumors of presumably neuroectodermal origin were stained with anti-laminin antibody by a double layered immunofluorescence technique. A marked positive staining for laminin was found in neurofibromas and neurilemmomas although the pattern of laminin distribution was slightly different. Accentuated staining was seen in Verocay bodies. In granular cell myoblastomas (GCM), small groups of tumor cells were encircled by laminin-positive material, whereas individual tumor cells were unstained. In nevi, diffusely spread nevus cells were surrounded by a rim of laminin, whereas when arranged in nests whole groups of cells were encircled by laminin as seen in the GCM. Ordinary oral fibromas included as controls were negative except for the expected positive staining of basement membranes normally occurring in the tissues. Immunohistochemical demonstration of laminin seems to be a valuable aid in differential diagnosis of soft tissue tumors and may provide useful information about the pathogenesis of various lesions.