Altered distribution of 1-2B7B antigen in basal cell carcinoma, squamous cell carcinoma and Bowen's disease

Skin lesions of basal cell carcinoma (BCC), squamous cell carcinoma (SCC) and Bowen's disease were immunohistochemically examined using the 1-2B7B monoclonal antibody, which recognizes a 120 kDa polypeptide component found in hemidesmosomes of normal human epidermis and hemidesmosome-like adhesion junction of vascular endothelial cells, to disclose altered characteristics of the interface between the tumor cell aggregate and stromal tissues of the epidermal neoplasms. In BCC, 1-2B7B antigen was rarely expressed at the tumor cell aggregate-stromal tissue interface, where poorly developed hemidesmosometonofibril complexes and a normal-looking lamina densa were detectable. In SCC and Bowen's disease, 1-2B7B antigen was expressed not only along the interface of the tumor nest and stromal tissue, but also in the intercellular space of the desmosomes and other adhesion junction structures that lack associating tonofibrils. In the invading front of SCC, 1-2B7B antigen had partly disappeared from the tumor cell aggregate-stromal tissue interface, where neither hemidesmosomes nor lamina densa were noted. The altered distribution of this hemidesmosomal component in the epidermal neoplasms seems to reflect aberrant interaction of neoplasmic cells and surrounding stromal tissue.