The relationship between serum squamous cell carcinoma related antigen (SCC-Ag) level and pathohistological view and/or stainability of tissue SCC-Ag was examined in oral squamous cell carcinoma. The specimens taken from 97 patients were stained with a monoclonal antibody against the SCC-Ag by immunoperoxidase methods. The serum SCC-Ag level was measured by a radioimmunoassay system. The well-differentiated carcinomas were stained well with this antibody, whereas the poorly-differentiated cases were stained weakly or negatively. Serum SCC-Ag levels were significantly high in the cases of invasive carcinoma, but not in the well differentiation of the tumors cases and in the well stained cases. These observations suggested that the parenchymal-stromal relationship is decisive factors in determining the serum SCC-Ag level.
