Biomarker Test May Be Useful for Detection of Bladder Cancer Cells in Urine

The use of fluorescence in situ hybridization (FISH) to determine the number of copies of the Aurora kinase A (AURKA) gene in urothelial cells isolated from urine is a possible biomarker test for the detection of bladder cancer.  Aurora kinase A is a key regulator of chromosome segregation during cell division. Overexpression of this protein is common in cancers, including bladder cancer, and leads to missegregation of chromosomes and aneuploidy.

In the current study, Bogdan Czerniak, M.D., Ph.D., of the University of Texas M. D. Anderson Cancer Center in Houston and colleagues overexpressed Aurora kinase A in urothelial cells in vitro and then measured chromosome copy number. The team examined the expression level of AURKA in patient biopsy samples. They also used FISH to examine the number of AURKA gene copies in cells isolated from the urine of 23 bladder cancer patients and 7 healthy control subjects to devise a biomarker test for bladder cancer detection. The biomarker test was validated on an independent group of 100 bladder cancer patients and 148 control subjects.

Forced overexpression of the AURKA gene induced aneuploidy and genomic instability in urothelial cells in vitro. The protein was overexpressed naturally in patient tumor samples. Using the FISH test for the AURKA gene, the researchers were able to accurately identify 87% of the bladder cancer patients and correctly categorize the control subjects as not having bladder cancer 96.6% of the time.  "Our findings suggest that the AURKA FISH test may be more effective than cytology in detecting bladder cancer," the authors write.