S-100 antigen labels neoplastic cells in liposarcoma and cartilaginous tumours.

S-100 antigen, originally believed to be unique to the nervous system, has recently been found in cell types of non-neuroectodermal origin such as chondrocytes and adipocytes. These findings suggested the possibility of detecting the antigen in tumours derived from such cells. Using the PAP method and an anti-ox brain S-100, the antigen was found in the cells of human chondrosarcomas, chondroblastomas and liposarcomas. In contrast, fibrous histiocytomas and fibrosarcomas, tested to verify the cellular specificity of the S-100 immunoreaction, did not exhibit S-100-containing cell types. The present data indicate the usefulness of the S-100 antigen as a diagnostic and investigative tool in defined neoplasms of non-neuroectodermal origin, such as chondroid tumours and liposarcoma.