Tumor-associated antigens in the urine of patients with bladder cancer

Previous work in our laboratory has demonstrated that antisera to proteins found in the urine of bladder cancer patients can distinguish between urine samples from these patients and those from normal individuals when tested by a complement-fixation assay. Antisera which were reactive with individual tumor-associated antigens were used to detect the antigens in the urine of bladder cancer patients and control individuals. One antigen was found in 66% of the bladder cancer patients (n = 38) and 25% of control individuals (n = 20). This antigen is a glycoprotein with a molecular weight of about 200,000 and beta-electrophoretic mobility and is distinct from carcinoembryonic antigen. A second molecule detected by an antiserum to urine fractions proved to be completely identical to serum C-reactive protein. C-Reactive protein was found in the urine of 72% of the bladder cancer patients (n = 39) and 32% of the control population (n = 32). Although a third protein detected with these antisera proved to be a normal urinary component, two of these tumor-related proteins appear to have potential as diagnostic markers for bladder cancer.