CHARACTERIZATION OF THE DD23 TUMOR-ASSOCIATED ANTIGEN FOR BLADDER-CANCER DETECTION AND RECURRENCE MONITORING

Bladder cancer detection, monitoring, and prevention represent major p roblems that could be addressed with sensitive and specific biomarkers . The antigen recognized by the DD23 antibody, previously developed ag ainst a tumor-related antigen, was partially biochemically characteriz ed, and its sensitivity and specificity in cancer detection and recurr ence monitoring was evaluated, Quantitative fluorescence image analysi s was used to quantify antigen content in exfoliated urothelial cells in a cross-section of patients with bladder cancers of all grades and stages and control populations, The antigen was found in tumor cells a s well as normal-appearing urothelial cells, suggesting it represents a marker induced by the altered growth factor environment of a cancer- containing bladder, When used as a quantitative marker, the sensitivit y for bladder cancer detection was 85%, and the specificity was 95%, N o significant difference was seen between symptomatic and asymptomatic control populations, including patients with previous bladder cancers in the absence of a recurrence, In bladder cancer recurrence monitori ng, results were consistently negative until just before detection of a recurrence, The biomarker reflects a ''field effect'' that occurs ve ry late in tumorigenesis and seems to represent events common to most cancers involving the genitourinary tract, Western blotting showed the antibody recognized a dimeric protein, DD23 quantification in single cells may be particularly useful in targeting cystoscopic intervention for recurrence monitoring and, because of its high specificity, could be a tool for bladder cancer screening in high-risk groups.