Keratin phenotypes in Basal-cell carcinomas of the skin.

Immunohistochemical profiles of 23 cases of basal cell carcinoma (BCC) were examined and compared with adjacent normal skin using three keratin antibodies, 34betaB4, 312C8-1 and E3, which recognize keratin 1, 14 and 17, respectively. In normal skin, 34betaB4 was expressed in suprabasal cells of the epidermis, sebaceous duct cells and the outer root sheaths of hair follicles at the level of sebaceous duct insertion. 312C8-1 was seen in basal cells of the epidermis, the outer root sheaths of hair follicles, and the peripheral cells of sebaceous glands. E3 was detected in the outer root sheaths of hair follicles, and the peripheral cells of sebaceous glands, while it was absent in the epidermis. In BCC, 312C8-1 and E3 were homogeneously found in all 23 cases, and 34betaB4 was sporadically expressed in 3. Therefore. the results suggest that the keratin expression of BCC resembles that of the pilosebaceous apparatus.