Carcinoma-specific keratin polypeptide patterns in keratinizing epithelia of rodents : independence of species- and tissue-specific variations.

A comparative investigation of the one- and two-dimensional electrophoretic keratin polypeptide patterns of various keratinizing epithelial tissues and of benign and malignant tumors of these tissues in the rodent species mouse, rat and hamster was undertaken. Keratin polypeptides of all normal epithelia investigated (vaginal, anal and forestomach epithelium) appear in a molecular weight range of about 40 K--70 K daltons and can be divided according to molecular weight and electrical charge into three groups. The large keratins (group A) have a basic character, while the lower molecular weight components of groups B and C are acidic in nature. The tissue-specific variations within one species are minimal and, apart from minor quantitative differences, mainly concern differing numbers of components within groups A and B, whereas the species-specific variations are more pronounced and apply to all three groups of keratins, which show a variable number of individual polypeptides differing in molecular weights and/or electrical charge. Independent of the tissue- and species-specific differences, keratins of epithelial carcinomas exhibit a special pattern differing from that of their corresponding intact tissues, as well as from benign tumors, by the lact of the large keratin polypeptides of group A. These characteristic differences in the keratin polypeptide composition of normal epithelia and of benign and malignant tumors may be useful for the diagnosis of epithelial tumors.