Detection of malignant cells in voided urine from patients with bladder cancer, a novel monoclonal assay.

A simple assay is described for detecting malignant cells in the voided urine from patients with transitional cell carcinoma of the bladder. Agarose-embedded urothelial cells from 24 biopsy-proven cancer patients and 10 controls were stained for surface immunofluorescence with four monoclonal antibodies reactive with human bladder cancer and three monoclonals reactive with blood group A. Reactivity was assessed by fluorescence microscopy. One antibody, BLCA-8 appeared to have particular diagnostic utility. Thus, 24.3 +/- 5.8 percent of outer layer and 27.0 +/- 4.6 percent of inner layer urothelial cells reacted with BLCA-8 in patient samples, compared to 2.9 +/- 1.0 and 0.8 +/- 0.5 percent of similar cells from control urines. BLCA-8 antigen expression was found to be relatively stable even after prolonged exposure to urine. In a comparison with conventional cytology, samples from 4/8 patients were considered positive by standard methods, whereas, 8/8 were BLCA-8 positive. This new technique may thus be a useful adjunct to conventional methods.