Development of noninvasive methods for the diagnosis of transitional cell carcinoma (TCC) of the bladder remains a challenge. A ProteinChip technology (sur-faceBladder cancer is the second most common genitourinary malignancy accounting for ϳ5% of all newly diagnosed cancers in the United States. 1 More than 90% are of the transitional cell carcinoma (TCC) histology. 2 At present, the most reliable way of diagnosis and surveillance of TCC is by cystoscopic examination and bladder biopsy for histological confirmation. The invasive and labor-intensive nature of this procedure presents a challenge to develop better, less costly, and noninvasive diagnostic tools. Urine cytology has for many years been the gold standard of the noninvasive approaches. It has high specificity and provides the advantage over biopsy of screening the entire urothelium. 2,3 However, its high false-negative rate, particularly for low-grade tumors, has limited its use as an adjunct to cystoscopy.Many noninvasive molecular diagnostic tests have been developed based on an ever-increasing knowledge about the molecular alterations associated with bladder cancer pathogenesis. The bladder tumor antigen, 4 the bladder tumor antigen stat, 5 the fibrinogen/fibrin degradation products, 6 and the nuclear matrix protein-22 tests, 3,7 have been approved by the Food and Drug Administration to be used in conjunction with cystoscopy. Additional molecular assays currently being evaluated for their diagnostic/prognostic utility 2,3,8,9 are the Telomerase, 10