Electrophoretic study of keratin polypeptides in chemically-induced oral carcinomas in the hamster

Comparison was made of the electrophoretic keratin polypeptide patterns of normal hard palate epithelia from three hamsters and of eight palatal squamous cell carcinomas induced by 7,12-dimethylbenz(a)anthracene (DMBA) treatment. Keratin polypeptides from normal epithelia had a molecular weight range of about 48,000 to 70,000. In the tumour extracts, the large polypeptides (above 61,000) found in the normal epithelia were absent, but the majority of other small polypeptides below 61,000 were expressed. Three as yet undefined polypeptides, in the range of 40,000 to 70,000, were detected in tumour extracts, but not in extracts of normal palatal mucosa. The keratin polypeptide electrophoretic alterations in carcinomas of hamster palatal mucosa are similar to those reported for extra-oral carcinomas in other animal species.