Immunohistochemical distinction of human carcinomas by cytokeratin typing with monoclonal antibodies.

Carcinomas of different origin have been tested in immunofluorescence microscopy with the monoclonal murine antibodies CK1-CK4, which recognize a single cytokeratin polypeptide (human cytokeratin No. 18) present in simple but not in stratified squamous epithelia, and with the monoclonal antibody KG8.13 and guinea pig kerA antibodies, both of which recognize a variety of cytokeratins common to almost all epithelial cell types. Tumors derived from simple epithelia, including adenocarcinomas and some other tumors such as ductal breast carcinomas, were strongly stained by all three antibodies. So was a transitional carcinoma of the bladder. In contrast, basal cell epithelioma, cloacogenic carcinoma, and squamous cell carcinoma of skin, tongue, and esophagus appeared negative with CK1-CK4 but positive with the other two antibodies. Other squamous cell carcinomas derived from epiglottis and cervix uteri showed a mixture of positive and negative cells when tested with CK1-CK4, although all tumor cells were positive when tested with KG8.13 and with kerA. Thus, use of an appropriate collection of cytokeratin antibodies with different specificities not only allows tumors of epithelial origin to be distinguished from other tumor types but, in addition, allows a further subdivision of carcinomas in relation to their histologic origin.     

Coexpression of intermediate filaments in squamous cell carcinomas of upper aerodigestive tract before and after radiation and chemotherapy

Frozen sections of 48 squamous cell carcinomas and seven undifferentiated carcinomas of the upper aerodigestive tract were investigated immunohistochemically with monoclonal antibodies specific for keratin, vimentin, desmin, neurofilaments, and glial fibrillary acidic proteins. In nine squamous cell carcinomas (19%) and six undifferentiated carcinomas (86%) obtained before treatment coexpression of keratin and vimentin was detected in some tumor cells by double immunofluorescence studies. Nine squamous cell carcinomas expressed neurofilaments in scattered tumor cells. Coexpression of vimentin or neurofilaments was seen especially in the peripheral cell layer of the tumor nests and did not seem to correlate with the degree of differentiation. Three undifferentiated carcinomas additionally expressed desmin, and one tumor contained neurofilaments. Glial fibrillary acidic proteins were not detected. Increased coexpression of keratin with vimentin, desmin, or neurofilaments was seen in some tumors that were studied before and after radiation/chemotherapy, suggesting that the intermediate filament profile of tumor cells can be altered by external influences.