DUAL-PARAMETER IMMUNOFLOW CYTOMETRY - A NEW TECHNIQUE IN THE NONINVASIVE DIAGNOSIS OF BLADDER-CANCER

The introduction of monoclonal antibodies into the diagnosis of transi tional cell carcinoma (TCC) has been a further step toward the use of biological parameters to support conventional cytological diagnosis of this tumor entity. Several investigators have demonstrated the high s ensitivity and good specificity of immunocytology. Nevertheless this t echnique is hampered by the inconvenient and time-consuming microscopi c analysis. The purpose of this study was to combine the advantages of immunocytology with the capabilities of an automated flow-cytometric system. Since all monoclonal antibodies (mAbs) currently used for immu nocytology cross-react with granulocytes a preselection of urothelial cells becomes necessary for immune-flow cytometry (immuno-FCM). Based on earlier analyses mAb Due AUT 2, reactive against urothelium and not against granulocytes, was chosen to preselect for urothelial cells. m Ab Due ABC 3 was used to discriminate between normal and malignant uro thelial cells. Initial experiments including 10 barbotage specimens fr om patients with histologically proven TCC and concomitant urinary tra ct infection yielded a high sensitivity (90%) of immuno-FCM. In 10 con trol patients with malignancies other than bladder TCC and benign dise ases ABC 3 expression was not increased. Flow-cytometric examination o f irrigation specimens from 10 patients with a history of bladder canc er but without cystoscopic and cytologic evidence of tumor recurrence showed abnormal results in 6 patients. Rebiopsy and/or cystectomy conf irmed tumor recurrence in 5 of these patients and in 1 patient with ne gative immuno-FCM. Ongoing prospective trials will further define the clinical impact of this approach in the diagnosis and follow-up of pat ients with bladder cancer.