Our overall objective continues to be the development of a clinically reliable system for detection, evaluation and monitoring of bladder cancer by flow cytometry (FCM). Prototypes developed and presently in use in our laboratory indicate that this is a feasible, near-term goal, and that quantitative information on additional cell features can be developed to provide a means of estimating tumor behavior and responsiveness to therapy. The specific aims fall within two categories: 1) a more detailed evaluation of present instrumentation and techniques for DNA/RNA measurement, (a) to detect precancerous lesions of the bladder in high risk patients, (b) to distinguish between low, intermediate and high grade tumors, and (c) to quantify in sequential examinations the effect of various therapeutic modalities (ie. local resection, intravesical BCG, irradiation) in order to predict treatment success vs failure, and 2) to (a) improve instrumentation (a dual beam flow cytometer with corresponding increased capacity for simultaneous, multiparameter measurement and analysis), and, (b) develop methods for preparation and staining of cell samples that will permit simultaneous measurement of 3 or 4 cell features capable of subclassification according to differentiation, proliferative capacity, etc. This flow cytometry technique already provides cytologic diagnosis with accuracy comparable to high quality conventional cytology, without the requirement for personal judgment and special skills of an experienced cytopathologist, and it should be useful almost immediately in areas where conventional cytology is lacking or unreliable. Further, the quantitative nature and reproducibility of FCM examinations make them ideal for tracking progressive tumor development or assessing treatment effect. Cell feature measurements with improvements in instrumentation presently under development are expected to provide information on tumor behavior and perhaps aid in selection of therapy. Our evaluation of current and new FCM techniques will involve comparison of the histology of resected tumors with FCM of cell suspensions from an aliquot of the same tumor; comparison of bladder irrigation FCM with conventional cytology, cystoscopy and biopsy findings; and a comparison of sequential FCM examinations of patients under therapy, or free of disease and at risk of recurrence, with clinical findings and pathology. The new methods we will be developing will make use of a dual laser instrument (soon to be available to us) and three dye combinations (eg. DAPI, FITC and Phycoerythrin or DAPI, Pyronin Y and Phycoerythrin) to evaluate DNA, RNA and one or two of a variety of monoclonal antibodies.