New Perspectives on the Role of Liquid Biopsy in Bladder Cancer: Applicability to Precision Medicine

Abstract

Bladder cancer (BC) is one of the most common tumors in the world. Cystoscopy and tissue biopsy are the standard methods in screening and early diagnosis of suspicious bladder lesions. However, they are invasive procedures that may cause pain and infectious complications. Considering the limitations of both procedures, and the recurrence and resistance to BC treatment, it is necessary to develop a new non-invasive methodology for early diagnosis and multiple evaluations in patients under follow-up for bladder cancer. In recent years, liquid biopsy has proven to be a very useful diagnostic tool for the detection of tumor biomarkers. This non-invasive technique makes it possible to analyze single tumor components released into the peripheral circulation and to monitor tumor progression. Numerous biomarkers are being studied and interesting clinical applications for these in BC are being presented, with promising results in early diagnosis, detection of microscopic disease, and prediction of recurrence and response to treatment.

Keywords: bladder cancer; immunotherapy; liquid biopsy; precision medicine.

Figure 1

Overview of liquid samples and biomarkers in bladder cancer. Liquid biopsy is emerging as a promising method. It involves using peripheral blood or urine samples for the collection and examination of six tumor components: CTCs, ctDNA, ctRNA, exosomes, metabolomics, and proteomics. Peripheral blood and urine samples are then used to extract and examine tumor components.

Figure 2

Major liquid biopsy methods in bladder cancer. Comparison of their clinical applications, laboratory analytical techniques, main advantages, and limitations.