DNA in Urine May Detect Bladder Cancer
According to an article recently published in the Journal of the National Cancer Institute, testing a small number of genes in a urine sample may help detect bladder cancer. These results need further confirmation, but may provide a non-invasive, effective method to screen for bladder cancer.
Bladder cancer is common; approximately 55,000 new cases are diagnosed in the U.S. each year. Superficial bladder cancer refers to cancer that has not spread to muscles of the bladder or nearby lymph nodes. Recurrence of superficial bladder cancer is common and often involves cancer invading the muscle of the bladder. Surgery is then required to remove the cancer.
Patients who have undergone initial treatment for superficial bladder cancer often receive follow-up cystoscopies to detect a recurrence. During a cystoscopy, a physician places a lighted tube into the bladder to search for abnormal areas of tissue that indicate cancer. Since the cystoscope must be inserted into the bladder, cystoscopy is an invasive procedure?a notable limitation of this test.
A less invasive way to detect bladder cancer recurrence is urinary cytology. With urinary cytology, a pathologist examines cells from a urine sample in order to find cancer cells that have been shed from the wall of the bladder. Urinary cytology, however, misses a fairly high proportion of low-grade (less aggressive) cancers. Given the limitations of both procedures, researchers are exploring tests that are less invasive than cystoscopy and more accurate than urinary cytology.
Researchers from Johns Hopkins Medical Institutions recently conducted a clinical study to evaluate the accuracy of detecting bladder cancer by testing of a small number of genes from a urine sample. This study included 175 patients with all different stages (extent of spread) of bladder cancer and 94 patients without bladder cancer. DNA from urine samples was tested to find a small number (panel) of genes with properties that indicated of the presence of bladder cancer.
- 82% of bladder cancers were identified from testing of the gene panel.
- 96% of tests that were positive for bladder cancer were accurate in the diagnosis.
The researchers concluded that the testing of this specific panel of genes within a urine sample identifies the presence of bladder cancer with high accuracy compared to standard testing. Further testing of this gene panel is required to confirm its accuracy and potential use in a clinical setting.
Reference: Hoque M, Begum S, Topaloglu O, et al. Quantitation of Promoter Methylation of Multiple Genes in Urine DNA and Bladder Cancer Detection. Journal of the National Cancer Institute. 2006; 98: 996-1004.