Squamous cell carcinoma-associated antigen in uroepithelial carcinoma.

We investigated the clinical significance of squamous cell carcinoma (SCC) antigen determined by radioimmunoassay on patients with uroepithelial carcinoma. Serum SCC antigen levels and the positive rates were significantly higher in uroepithelial carcinoma having an SCC component than in normal controls, benign urologic diseases, other urogenital carcinomas, or in pure transitional cell carcinoma (TCC) of uroepithelial carcinomas. A substantial number of patients with pure TCC showed a positive serum level of SCC antigen. Immunohistochemical staining of SCC antigen on the uroepithelial carcinomas confirmed that some, not all, pure TCC, mostly grade 3, expressed SCC antigen in their cells. These results suggested a biologic characteristic of grade 3 TCC which is closely related to that of SCC. The serum levels of SCC antigen correlated well with the disease extensions in uroepithelial carcinoma containing SCC component. Changes in serum levels of SCC antigen following treatment reflected the clinical courses of patients, particularly in those with elevated pretreatment levels. The results of our study indicated that the determination of SCC antigen would be clinically useful for monitoring clinical courses of patients with uroepithelial carcinomas containing SCC component and of those with pure TCC whose pretreatment level was elevated.