Monoclonal antibodies to various acidic (type I) cytokeratins of stratified epithelia. Selective markers for stratification and squamous cell carcinomas.

We determined the reactivity of two monoclonal antibodies to cytokeratins that are typically expressed in certain stratified epithelia and several human squamous cell carcinomas using immunoblotting techniques and immunofluorescence microscopy. Antibody KS 8.12 reacted specifically with cytokeratin polypeptides nos. 13 and 16, and stained noncornified squamous epithelia in a rather uniform way. The examination of diverse human carcinomas showed all squamous cell carcinomas to be positively stained with this antibody, whereas all adenocarcinomas were negative. Another antibody, KK 8.60, reacted with polypeptides nos. 10 and 11, and uniformly stained the suprabasal layers of the epidermis. In several noncornified squamous epithelia (e.g., tongue, exocervix), in thymus reticulum epithelial cells, and in moderately and well differentiated squamous cell carcinomas this antibody exhibited a nonuniform labeling pattern that allowed the detection of individual cytokeratin-10/11-positive cells scattered throughout the tissue. It is concluded that antibodies KS 8.12 and KK 8.60 represent specific molecular probes for the definition of certain stages of squamous differentiation in normal development as well as in pathological processes such as squamous metaplasia and carcinogenesis. We propose the use of these antibodies in the differential diagnosis of carcinomas and their metastases.