Liquid biopsy in genitourinary cancers: Diagnostic and prognostic implications

Genitourinary neoplasms, including bladder, prostate, renal, and testicular cancers, represent 25% of all solid tumors worldwide. Great advances have been achieved in the last few decades in diagnostic and therapeutic modalities. Among these, liquid biopsy (LB) technology has evolved during the past few years and offers emerging and novel modalities in the field of oncology. LB is performed by withdrawing bodily fluids (<i>i.e.</i>, blood or urine) and looking for circulating tumor DNA, circulating tumor cells, extracellular vesicles, and non-coding RNAs, among others. Over the past years, several technologies have been developed to isolate and analyze the tumor burden. LB is less invasive than traditional biopsies and has many applications, including early screening, providing diagnostic cues, predicting disease severity and survival outcomes, assessing response and resistance to treatment, detecting minimal tumor burden before radiological evidence, and monitoring for disease recurrence. However, multiple challenges still need to be addressed, including reduction in variability between assays, standardization of protocols, and validation in large trials to ensure reliability. This review will focus on the latest advancements in LB applications for diagnostic and prognostic characterization of genitourinary cancers.