[Immunohistochemical study of malignant fibrous histiocytoma]

Malignant fibrous histiocytomas (MFH) and other soft-tissue tumors were examined immunochemically (by the peroxidase-antiperoxidase technique) for the presence and location of alpha 1-antitrypsin (alpha 1-AT) and alpha 1-antichymotrypsin (alpha 1-ACT). alpha 1-AT and alpha 1-ACT were found in substantial amounts in 19 and 20 of the 20 MFH tumors examined, respectively. In the other soft-tissue tumors, they occurred inconsistently and in less than 50% of cells, mostly those with signs of damage. It is concluded that assays for alpha 1-AT and alpha 1-ACT may aid in the diagnosis and characterization of malignant fibrous histiocytoma.