Renal cell adenocarcinoma and retrovirus p30-related antigen excreted to urine

The authors have previously demonstrated in syncytiotrophoblastic cells of human placenta, hydatidiform and destructive moles, and choriocarcinoma antigens reacting with antibodies to the endogenous feline retrovirus RD114 p30 and human T cell leukemia-lymphoma virus p19 proteins. The authors now report that a monoclonal IgG1 antibody (HPS-1), recognizing both syncytiotrophoblasts and RD114 p30, also reacts with an antigen in the tumor cell cytoplasm of all 27 renal cell adenocarcinomas studied. Positively stained antigenic material was also seen in the lumen of normal tubuli of tumor kidneys, suggesting its excretion into urine. None of 10 normal kidneys, 17 Wilms' tumors, 5 transitional cell carcinomas of the renal pelvis, 5 similar tumors of the urinary bladder, 20 adenocarcinomas of the cervix uteri, 20 adenocarcinomas of the corpus uteri, or 20 adenocarcinomas of the colon showed any positive staining. All 3 renal oncocytomas studied gave a positive staining reaction. In RD114 p30 radioimmunoassay antigenic activity was detected in the urine of renal cell adenocarcinoma patients in amounts up to 1.93 ng/mg protein, but not in the serum. After nephrectomy, a decline of the excreted antigen was observed, the preoperative values being 0.16 to 1.93 ng/mg protein and the postoperative ones ranging from immeasurable to 0.58 ng/mg protein. The patients with measurable postoperative urine values had clinically detectable distant metastases. The p30-related antigen may provide a marker for renal cell adenocarcinoma.