Abstract
The distribution of intracellular keratin and lectin binding were studied in dysplastic lesions and squamous cell carcinomas of buccal pouch and lingual mucosae of the hamster induced by the application of a 0.5% DMBA mineral oil.
Comparison was made of the electrophoretic keratin polypeptide patterns of normal buccal pouch epithelia and of squamous cell carcinomas of buccal pouch mucosa. Keratin polypeptides from normal epithelia had a molecular weight (MW) range of about 47, 000 to 76, 000. In tumor extracts, the large polypeptides (above MW 58, 000), found in the normal epithelia, were absent. The majority of small polypeptides below MW 58, 000 were expressed. Antibodies against total keratin extracts from normal buccal pouch epithelia (NAG) and squamous cell carcinomas (CAAG) were raised in rabbits, respectively NAB and CAAB. NAB staining was strong in spinous cells but negative in basal cells, whereas CAAB staining was strong in spinous cells and moderate or weak in basal cells. The dysplastic epithelial cells and squamous cell carcinoma cells except for cancer pearls showed no staining for the NAB, but exhibited weak or moderate CAAB staining.
Lectin binding in normal squamous epithelium showed regional distribution patterns of spinous and basal layer types. Dysplastic cells or carcinoma cells displayed a loss of cellular surface and intercellular staining.
The present study suggests that the difference of the staining intensities of keratins using NAB and CAAB and the lectin binding among the normal epithelium, dysplasia and squamous cell carcinoma are valuable indicators of the malignant transformation in the oral mucosa of hamsters.
