A comparison of glycoprotein biosynthesis in benign and malignant squamous epithelioma and normal epidermis

Protein and N-linked glycoprotein biosynthesis was studied in histologically verified normal epidermis, actinic keratoses, keratoacanthoma, intra-epidermal carcinoma and squamous-cell carcinoma using polyacrylamide gel electrophoresis (PAGE). The PAGE profiles of 3[H]-leucine-labelled proteins and 3[H]-mannose-labelled glycoprotein from all disease states studied differed from each other and from normal epidermis. A large 3[H]-mannose-labelled glycoprotein region (band A) with a peak at 97-92 kDa appeared to indicate the presence of a relatively large proportion of basaloid cells in the tissue. An associated peak in the region of 78-74 kDa also appeared in normal epidermis and what appeared to be non-invasive lesions. The main region of change in all lesions corresponded to the 66-34-kDa region (bands B and C). The absence of a group of glycoproteins and proteins in the 62-58-kDa region appeared to be specific for invasive squamous-cell carcinoma. All tumours showed a peak at 38-34 kDa which was not present in normal epidermis. Actinic keratosis had a pattern similar to normal epidermis except that the peaks of band B tended towards the higher-molecular-weight end of the band than those in normal epidermis and peaks at 28-22 kDa were seen. The latter seemed to correspond to the presence of a high proportion of spinous cells in the tissue sample.