TRA-1-60: a new serum marker in patients with germ-cell tumors.

TRA-1-60 is a monoclonal antibody (MAb) that recognizes a mucin-like antigenic determinant expressed on the surface of embryonal carcinoma (EC) progenitor cells. In order to determine whether this antigen is released into the serum of patients with a non-seminomatous germ-cell tumor (NSGCT), we developed a sensitive 2-step immunoenzymometric assay. Of 42 EC-positive NSGCT patients tested, 32 (76%) were found to release TRA-1-60-reactive antigen into their serum, in contrast to 1 positive finding in 10 EC-negative NSGCT patients. The marker was found in 67% (10/15) of the EC-positive patients who were negative for both AFP and HCG. Sera from seminoma patients did not contain elevated levels of the TRA-1-60 antigen. Therefore, we propose that the TRA-1-60 antigen is a useful additional serum marker for following the progress of NSGCT(EC+) patients.