NOVEL CA2-BINDING S100 PROTEINS, GLIAL FIBRILLARY ACIDIC PROTEIN AND TENASCIN IN CHONDRO-OSSEOUS TUMORS()

The expression of Novel Ca2+-binding proteins S100A1, S100A2, S100A4, S100A6 and S100B; an intermediate filament protein. glial fibrillary a cidic protein (GFAP); and an extracellular matrix glycoprotein, tenasc in were evaluated in chondro-osseous tumors. The tumor specimens obtai ned from surgery and routinely processed for paraffin embedding were e valuated. The tumors were histologically diagnosed as chondroma (n=2), osteoma (n=2), chondrosarcoma (n=3), osteosarcoma (n=6) and Ewing's s arcoma (n=2). Chondrocytes or chondrometaplastic cells in both benign and malignant tumors as well as undifferentiated round, spindle and el ongated cells in chondrosarcoma and osteosarcoma showed an intense imm unoreactivity for S100B and occasionally for S100A6. S100A1 and S100A4 but not for S100A2. The intensity of immunostaining for osteosarcoma was less intense than that for chondrosarcoma. S100B reactive cells we re also reactive for GFAP, although the intensity of staining was less intense for GFAP. Reaction products for tenascin was seen in the matr ix of neoplastic cartilage in chondroma and chondrosarcoma, and uncalc ified osseous matrix in osteoma and osteosarcoma, and the immunoreacti ve areas of tenascin usually coincided with intensely reactive cells f or S100B in neoplastic chondroid tissue. The results reasonably allowe d to conclude that S100B may be a potential marker for the identificat ion of chondroid cells in neoplastic lesions and the Siege containing cells may express GFAP and may be associated with an enhanced expressi on of tenascin in the tumor matrix, the functional significance of whi ch is under investigation.