Circulating Cell-Free DNA in Liquid Biopsies as Potential Biomarker for Bladder Cancer: A Systematic Review

SIMPLE SUMMARY: Bladder cancer (BC) is one of the most frequent cancers in the world and the urological tumor that presents the highest mortality. The diagnostic and prognostic methods available at present for BC are expensive and highly invasive for the patient, so the pursue of biomarkers that may replace those methods has been ongoing for years with limited success. One of these potential biomarkers is cell-free DNA, which can be found in liquid biopsies such as urine and blood. The present review summarizes the most recent research findings in the study of cell-free DNA to diagnose BC and even monitor treatment. ABSTRACT: Bladder cancer (BC) is among the most frequent cancer types in the world and is the most lethal urological malignancy. Presently, diagnostic and follow-up methods for BC are expensive and invasive. Thus, the identification of novel predictive biomarkers for diagnosis, progression, and prognosis of BC is of paramount importance. To date, several studies have evidenced that cell-free DNA (cfDNA) found in liquid biopsies such as blood and urine may play a role in the particular scenario of urologic tumors, and its analysis may improve BC diagnosis report about cancer progression or even evaluate the effectiveness of a specific treatment or anticipate whether a treatment would be useful for a specific patient depending on the tumor characteristics. In the present review, we have summarized the up-to-date studies evaluating the value of cfDNA as potential diagnostic, prognostic, or monitoring biomarker for BC in several biofluids.