Keratin subsets in spindle cell sarcomas. Keratins are widespread but synovial sarcoma contains a distinctive keratin polypeptide pattern and desmoplakins.
The presence of individual keratin polypeptides and desmoplakins was immunohistochemically studied in 25 spindle cell sarcomas of different types using acetone-fixed frozen sections. Results revealed that keratins 8 and 18 were present in a high number of tumors: 9 of 9 synovial sarcomas, 5 of 7 leiomyosarcomas, 5 of 5 malignant schwannomas, and 1 of 4 undifferentiated spindle cell sarcomas. In addition to keratins 8 and 18, the glandular component of synovial sarcoma showed prominent reactivity with antibodies to keratins 7 and 19. Also the glandular epithelial cells in synovial sarcoma showed desmoplakin immunoreactivity preferentially in a luminal distribution, but desmoplakin was absent in other spindle cell sarcomas. Furthermore keratin 13 was seen focally in 4 of 9 synovial sarcomas. In contrast, keratins 7, 13, and 19 were practically absent in leiomyosarcomas, malignant schwannomas, and undifferentiated spindle cell sarcomas. The widespread presence of keratins 8 and 18 in various spindle cell sarcomas may reflect aberrant keratin expression in mesenchymal cells, previously described in cultured transformed fibroblasts. The presence of keratins 7 and 19 and desmoplakin is highly associated with morphologically observable epithelial differentiation restricted to synovial sarcoma among spindle cell sarcomas.
Miettinen
M
M
Department of Pathology and Cell Biology, Thomas Jefferson University, Philadelphia, Pennsylvania.
D003598:Cytoskeletal Proteins / Q000378:metabolism*; D051180:Desmoplakins; D003896:Desmosomes / Q000378:metabolism; D006801:Humans; D007633:Keratins / Q000378:metabolism*; D007890:Leiomyosarcoma / Q000378:metabolism / Q000473:pathology; D009442:Neurilemmoma / Q000378:metabolism / Q000473:pathology; D010455:Peptides / Q000378:metabolism; D010524:Peripheral Nervous System Neoplasms / Q000378:metabolism / Q000473:pathology; D012509:Sarcoma / Q000378:metabolism* / Q000473:pathology; D013584:Sarcoma, Synovial / Q000378:metabolism* / Q000473:pathology; D012983:Soft Tissue Neoplasms / Q000378:metabolism* / Q000473:pathology
D003598:Cytoskeletal Proteins; C495294:DSP protein, human; D051180:Desmoplakins; D010455:Peptides; D007633:Keratins