Altered expression of NU-T2-BMZ antigen and type VII collagen in basal cell epithelioma.

The cutaneous basement membrane zone (BMZ) is composed of a large number of molecular components. We have recently reported that one of the CD1b monoclonal antibodies (MoAb), NU-T2, reacts to the BMZ of the normal human skin, esophagus and stomach. In order to further elucidate the biological properties of the NU-T2-BMZ antigen, we investigated the expression of NU-T2-BMZ antigen and type VII collagen (well identified component of anchoring fibrils) in various skin tumors such as basal cell epithelioma (BCE), squamous cell carcinoma, Bowen's disease, actinic keratosis and seborrheic keratosis. NU-T2 MoAb failed to react to the BMZ in all BCE. Anti-type VII collagen MoAb showed reduced staining of the BMZ in some nests of BCE. Both antigens, however, were preserved in the BMZ of other skin tumors as in the normal adjacent skin. Furthermore, anti-type VII collagen MoAb demonstrated the clear intratumoral staining in all BCE examined. The abnormal expression of NU-T2-BMZ antigen and type VII collagen may partly explain the space formation between the BCE nests and the surrounding stroma frequently observed in histology.