Detection of cancer-associated antigen(s) in urine of sarcoma patients

Tumor-associated antigens were demonstrated in concentrated and dialyzed urine of several sarcoma patients with large tumor burden. The antigens were detected by complement fixation using autologous and allogeneic sera from sarcoma patients. The antigenic activity in three patients who were studied sequentially disappeared after surgical ablation of tumor. In two of these three patients, the antigenic activity reappeared before tumor recurrence. The reactivity of the sarcoma sera to the urine could be abolished by absorption of the sera with human sarcoma cells but not by normal human liver cells, which indicates that the same antigen was present in the urine and on biopsy-obtained sarcoma cells. Urine from cancer patients with high tumor burden may be useful as a source of tumor-associated antigen. Further studies on the presence of these antigens in urine of sarcoma patients may lead to a method for detecting subclinical tumor recurrence.