HUMAN CELL-ADHESION MOLECULE UVOMORULIN IS DIFFERENTIALLY EXPRESSED IN VARIOUS SKIN TUMORS

The cell adhesion molecule uvomorulin is important in cell recognition processes, both during tissue formation in embryonic development and in the maintenance of adult epithelia. In addition, uvomorulin appears to play a crucial role in carcinogenesis. Therefore, in the present s tudy, the expression of uvomorulin in normal human skin and several be nign and malignant proliferative skin lesions was evaluated by immunof luorescence microscopy using affinity purified antibodies. In normal h uman epidermis, basal and suprabasal keratinocytes showed a strong and homogeneous staining of the cell membrane. In contrast, uvomorulin ex pression was decreased in squamous cell, as well as in solid basal cel l, carcinoma. Interestingly, solid basal cell carcinoma showed a dimor phic staining pattern with a reduced fluorescence of the inner cell la yers and normal staining of the peripheral basal cells. In contrast, n o such dimorphic staining pattern could be observed in squamous cell c arcinoma, in which uvomorulin expression was homogeneously reduced. De creased expression of uvomorulin was not specific for malignant skin l esions, since it could also be observed in condylomata acuminata. Thes e studies demonstrate that human uvomorulin is differentially expresse d in proliferative skin disorders, which may account at least in part for the differences observed in the clinical course between squamous c ell and basal cell carcinoma.