Antibodies to different intermediate filaments as histogenetic tumormarkers

Fifty primary carcinomas, nineteen nonmuscular sarcomas, ten rhabdomyosarcomas, one malignant ependymoblastoma and seventeen sympathetic derived tumors have been studied to determine what type of intermediate filaments they express, using affinity purified antibodies to prekeratin, vimentin, desmin, glial fibrillary acidic protein (GFA) and to the different neurofilament proteins. The tissue was ethanol fixed and paraffin embedded before use. In all carcinoma cases the tumor cells are stained by antibodies to prekeratin, whereas tumor cells in nonmuscular sarcomas could only be labeled by antibodies to vimentin. In the cases of rhabdomyosarcomas tumor cells are clearly decorated by antibodies to desmin. The one case of malignant ependymoblastoma was positive when tested with antibodies directed against glial fibrillary acidic protein (GFA). While most of the sympathetic derived tumors react positively with sera directed against the different neurofilament proteins, three neuroblastomas did not react with sera against any of the known intermediate filament types. Wider use of such sera would seem particularly useful in cases such as neuroblastomas, undifferentiated carcinomas, lymphomas and rhabdomyosarcomas.