Carcinoembryonic antigen and related antigens expressed on keratinocytes in inflammatory dermatoses

Carcinoembryonic antigen (CEA) is recognized as being important not only as a tumour marker, but also as a cell adhesion molecule in the metastasis of malignant tumour cells, and in the development of inflammatory disorders in some organs. However, the role played by this antigen in inflammatory dermatoses has not been studied previously. To investigate the expression of CEA in inflamed skin, we performed immunohistochemical studies to detect the antigen in both frozen and formalin-fixed, paraffin-embedded biopsy specimens of inflammatory dermatoses, using five different monoclonal antibodies and one polyclonal antibody against human CEA or CEA-related molecules. CEA and CEA-related antigens were expressed by epidermal keratinocytes and by some infiltrating inflammatory cells in inflamed skin. The expression was observed primarily in the upper part of the malpighian layers of the epidermis. On the basis of the distribution of this expression, we suggest an additional role for CEA-related molecules, differing from their roles as tumour markers and adhesion molecules, namely that these molecules may be associated with the state of differentiation of epidermal keratinocytes. Unexpected expression of CEA-related antigens was seen on normal follicular keratinocytes. Thus, it is conceivable that CEA-related antigen may also play a role in the biology of hair follicles.