Diagnosing Bladder Cancer using Urinary Cell-Free microRNA - Expert Commentary

Although hematuria is the most common symptoms of bladder cancer (BC), it can be caused by many non-malignant conditions. The low sensitivity of voided urine cytology (VUC) and the invasiveness the cystoscopy, create an unmet need for a noninvasive test with high accuracy to detect BC in patients with hematuria. 

A new paper published in the International Journal of Cancer developed a new non-invasive accurate method of detecting BC by using the urinary cell-free microRNA (miRNA). The investigators obtained 543 urine samples from the National Biobank of Korea between 2000- 2015 including 326 BC and 217 non-BC control samples (174 hematuria and 43 pyuria without cancer). The investigators used miRNA microarray screening and determining the receiver operating characteristics (ROC) specificity of their new method. They compared the ratio of urinary cell-free miR-6124 (up-regulated in BC urine) to miR-4511 (down-regulated in BC urine) in BC patients to the non-BC control group.

The investigators found that the BC samples have significantly higher expression ratio of urinary miR-6124 to miR-4511 in comparison to the non-BC control group at a sensitivity of >90%. They did not observe any significant difference in the ratio of miR-6124 to miR-4511 between muscle-invasive bladder cancer and non-muscle invasive bladder cancer groups. When they compared the urinary miRNA biomarker to VUC, they found that the sensitivity of the urinary miRNA biomarker was significantly higher than that of VUC in detecting any grade of BC. The investigators propose using this test to triage patients presenting with hematuria. 

This study sheds light on the growing field of diagnostics based on cell-free urinary DNA and RNA. Such minimally invasive methods will need to be tested prospectively to determine their impact on clinical outcomes.

Written by: Bishoy M. Faltas, MD, Weill Cornell Medicine, New York, NY

Read The Abstract 

Piao XM, Jeong P, Kim YH, Byun YJ, Xu Y, Kang HW, Ha YS, Kim WT, Lee JY, Woo SH, Kwon TG, Kim IY, Moon SK, Choi YH, Cha EJ, Yun SJ, Kim WJ. Int J Cancer. 2018 Sep 5. doi: 10.1002/ijc.31849.
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