DD23 Biomarker: A prospective clinical assessment in routine urinary cytology specimens from patients being monitored for TCC

Background: A prospective clinical study was conducted to assess the ability of the DD23 murine monoclonal antibody to enhance detection of bladder cancer in routine alcohol fixed urine cytology samples. Methods: Prospectively, 308 bladder cytology specimens were obtained from patients with a history of bladder cancer with a mean age of 71.4±11.9 (27% female, 73% male). Data included 121 biopsy-confirmed results and 187 cystoscopy results to assess presence or absence of cancer. Thirty-five normal cytology specimens were obtained from asymptomatic men and women between 55–85 years of age. Separate slides from the alcohol fixed cytology specimens were stained using the Papanicolaou (Pap) and Feulgen staining procedures. The DD23 assay was performed using an avidin-biotin alkaline phosphatase immunocytochemical procedure, with a single urothelial cell exhibiting intense immunostaining sufficient to make a positive call. RESULTS: Pap-Feulgen cytopathology for the 308 cases yielded an overall sensitivity of 65.5% and a specificity of 85.1%, and the DD23 biomarker alone yielded a sensitivity of 80.5% and a specificity of 59.7%. Analysis of the voided urines only (n=164) yielded sensitivities of 61.0% and 73.2% and specificities of 86.2% and 67.5% for cytopathology and DD23 alone, respectively. Results in 49 bladder wash urine cytology cases produced a sensitivity of 70.2% and 100% and specificities of 92.3% and 61.5% for cytopathology and DD23 alone, respectively. In 133 patients that underwent biopsy or had positive cystoscopy results, cytopathology yielded a sensitivity of 65.5% and a specificity of 69.6% while DD23 yielded a sensitivity of 80.5% and a specificity of 58.7%. In 25 biopsy-confirmed low-grade cancers, DD23 improved cancer detection from 32% to 72% when compared to cytopathology. The DD23 biomarker had a specificity of 85.7% in 35 age-matched normal asymptomatic control specimens. Conclusions: The DD23 biomarker is an adjuvant test that provides improved detection of bladder cancer in cytology specimens and enhances the sensitivity of the cytopathology diagnosis, especially in low-grade cancers.