Is aneusomy of chromosome 9 alone a valid biomarker for urinary bladder cancer screening?

Detection of genetically-changed tumor cells in the urine is one of the new approaches for the screening of bladder carcinomas. In a previous study, numerical aberrations of chromosome 9 were found in 85.18% of bladder tumors studied by the fluorescence in situ hybridization (FISH) technique. The purpose of the present study was to investigate whether chromosome 9 aneusomy alone is a valid, cost effective, biomarker for bladder cancer screening.

Twenty-seven voided urine specimens obtained from 22 bladder cancer patients, either at initial diagnosis or at the follow-up, were analyzed by the FISH technique with the centromeric probe specific for chromosome 9.

In all except 2 out of the 13 specimens with a histological confirmation of cancer, FISH analysis showed aneusomy 9 (sensitivity 84.61%). Among 6 cases with a negative cystoscopy but a positive FISH analysis, 3 recurred within the following 2 months, while 2 no-recurrent patients continued to show positive FISH findings after 6 months. One patient was considered to be false-positive. Four cases with a negative cystoscopy showed disomy 9 and 2 of them recurred.

Aneusomy 9 has a high sensitivity (84.61%) for the detection of bladder cancer. Patients with a negative cystoscopy but with aneusomy 9 should be kept under close clinical surveillance for potential disease recurrence. However, negative FISH results might not be a negative predictor for disease recurrence. Our results encourage further studies with a large number of patients and a long-term follow-up with concurrent FISH analysis.