Development of an enzyme immunoassay to detect and quantitate tumor-associated antigens in the urine of sarcoma patients.

This study describes the development of an enzyme immunoassay (EIA) to quantitate antigen in the urine of sarcoma patients and compares its results with those of the authors' previously reported complement fixation assay. Three populations were studied for the presence of urinary antigen by EIA: (1) sarcoma patients who developed metastatic disease after resection of their primary tumor; (2) sarcoma patients who remain clinically disease-free two years after resection of their primary tumor; and (3) normal volunteers with no history of malignant disease. EAch group consisted of nine individuals. None of the urines from normal volunteers and none from sarcoma patients who remained free of disease for two years had elevated antigen titers detectable by EIA. However, all nine patients who developed pulmonary metastatic disease ahd significantly elevated levels of antigen in their urine prior to clinical evidence of disease recurrence. The day-to-day fluctuations in antigen titer detectable by EIA tended to parallel the levels detected by the complement fixation assay. However, EIA detected a significant elevation in antigen titer one to four months earlier than the complement fixation assay in four of the patients in whom disease recurred.