CD30 ANTIGEN IN EMBRYONAL CARCINOMA AND EMBRYOGENESIS AND RELEASE OF THE SOLUBLE MOLECULE

The expression, serological detection, and possible functional role of the CD30 antigen in Hodgkin's disease and anaplastic large cell lymph oma is well documented. In embryonal carcinoma (EC), the expression of this cytokine receptor has been demonstrated only by immunohistology. Because the CD30 monoclonal antibody Ki-1 was found to cross-react wi th an unrelated molecule, we examined by in situ hybridization testicu lar germ cell neoplasms for the presence of CD30-specific transcripts. CD30 mRNA was detectable in the tumor cells of 9 of 9 cases of EC or mixed germ cell tumors with an EC component but in no other nonlymphoi d tumors. Thus, the CD30 transcript expression pattern proved to be id entical to the immunostaining pattern seen with the CD30-specific mono clonal antibody Ber-H2. By Northern blot analysis, CD30 transcripts co uld be demonstrated in the EC cell line Tera-2. Employing a highly sen sitive second generation sandwich enzyme-linked immunosorbent assay, w e could detect the soluble CD30 molecule in 8 of 8 sera from patients with a diagnosis of EC but not in 8 of 10 sera from patients with othe r testicular germ cell tumors. In fetal tissue, no CD30-expressing ger m cells or epithelial cells could be observed. Thus, the cellularly ex pressed CD30 molecule appears to represent a real tumor marker for tes ticular neoplasms of EC type. Moreover, the serum levels of soluble CD 30 antigen seem to be a promising parameter for monitoring patients wi th EC.