Value of urinary topoisomerase-IIA cell-free DNA for diagnosis of bladder cancer

Purpose: Topoisomerase-II alpha (TopoIIA), a DNA gyrase isoform that plays an important role in the cell cycle, is present in normal tissues and various human cancers, and can show altered expression in both. The aim of the current study was to examine the value of urinary TopoIIA cell-free DNA as a noninvasive diagnosis of bladder cancer (BC). Materials and Methods: Two patient cohorts were examined. Cohort 1 (73 BC patients and seven controls) provided bladder tissue samples, whereas cohort 2 (83 BC patients, 54 nonmalignant hematuric patients, and 61 normal controls) provided urine samples. Real-time quantitative polymerase chain reaction was used to measure expression of TopoIIA mRNA in tissues and TopoIIA cell-free DNA in urine samples. Results: The results showed that expression of TopoIIA mRNA in BC tissues was significantly higher than that in noncancer control tissues (p<0.001). The expression of urinary TopoIIA cell-free DNA in BC patients was also significantly higher than that in noncancer patient controls and hematuria patients (p < 0.001 and p < 0.001, respectively). High expression of urinary TopoIIA cell-free DNA was also detected in muscle invasive bladder cancer (MIBC) when compared with nonmuscle invasive bladder cancer (NMIBC) (p=0.002). Receiver operating characteristics (ROC) curve analysis was performed to examine the sensitivity/specificity of urinary TopoIIA cell-free DNA for diagnosing BC, NMIBC, and MIBC. The areas under the ROC curve for BC, NMIBC, and MIBC were 0.741, 0.701, and 0.838, respectively. Conclusions: In summary, the results of this study provide evidence that cell-free TopoIIA DNA may be a potential biomarker for BC.