alpha-chymotrypsin and Soft-Tissue-Neoplasms

We have studied the possible origin of histiocytic cells, present in fibrous histiocytomas (MFH) by using immunohistochemistry to demonstrate lysozyme, alpha 1-antitrypsin, alpha 1-antichymotrypsin and receptors for peanut and soy bean agglutinin in tumour cells of MFH compared with their presence in tumour cells of malignant histiocytosis (MH) ('true' histiocytic lymphoma, 'true' histiocytic sarcoma). We included in this study a number of other soft tissue tumours (STT). Lysozyme was detected in half of the cases of malignant histiocytosis (n = 16) but in only two out of 77 MFH. alpha 1-Antitrypsin and alpha 1-antichymotrypsin usually occurred together although the latter was seen in more cases. Both markers were present in majority of cases of MH whereas they were detected in a minority of cases of MFH. MFH cases of the storiform subtype were less frequently stained than the pleomorphic or giant cell subtypes. Receptors for peanut or soy bean agglutinin were detected in nearly all MH cases, whereas their presence was only detected in a small number of MFH. Lysozyme was not detectable in other STT. alpha 1-Antitrypsin and alpha 1-antichymotrypsin were uncommonly present in other STT, except in osteosarcoma and rhabdomyosarcoma. These markers therefore have a limited value as indicators of a possible histiocytic origin of MFH. Lectins showed weak affinity for other STT. In accordance with others, we therefore conclude that the progenitor cell of MFH has to be sought within the undifferentiated mesenchymal cells and that histiocytes themselves probably do not give rise to MFH.

Topics: alpha 1-Antichymotrypsin; alpha 1-Antitrypsin; Chymotrypsin; Histiocytoma, Benign Fibrous; Humans; Immunoenzyme Techniques; Lectins; Lymphatic Diseases; Muramidase; Plant Lectins; Receptors, Mitogen; Soft Tissue Neoplasms; Soybean Proteins

Until recently, the diagnosis and classification of malignant fibrous histiocytomas (MFH) has been based on light- and electron-microscopic appearances. Tissue culture studies have led to the suggestion that these tumors have a common histiocytic origin. Using the immunoperoxidase PAP technique, a variety of soft-tissue tumors have been stained for the histiocyte markers alpha-1-antitrypsin (A1AT), alpha-1-antichymotrypsin (A1ACT) and lysozyme. A1AT and A1ACT are found to be useful specific markers for tumors of the MFH group whereas lysozyme is not a reliable marker for such tumors. The presence of these substances within the tumors supports the theory that they share a common origin from tissue histiocytes. Only a proportion of superficial skin histiocytomas stain for A1AT and A1ACT, raising the possibility that these are a heterogeneous group and do not share a common histogenesis with MFH.

Topics: alpha 1-Antichymotrypsin; alpha 1-Antitrypsin; Chymotrypsin; Histiocytoma, Benign Fibrous; Humans; Immunoenzyme Techniques; Muramidase; Soft Tissue Neoplasms