Cancer exosomes in urine: a promising biomarker source

In face of innovative therapeutic strategies for cancer diagnosis and treatment, and of the elusiveness of renal and urinary tract tumors, the identification of novel biomarkers for diagnosis, prognosis, selection and monitoring of therapies is a primary target of research. The concept of "precision medicine" for tailoring the oncologic management in a minimally invasive fashion is considered a new epoch in cancer management. Extracellular vesicles, and exosomes in particular, carry lipids, mRNAs, non-coding RNAs, DNA, and active proteins, are present in a variety of bodily fluids including urine. In fact, urinary exosomes contain most of the urinoma proteins. Exosomes are nanovesicles originating from an endocytic pathway of the endocellular membranes and upon release are actors of intercellular communication, able to induce phenotypic changes including tumorigenesis and metastasis, in recipient cells. Tumor-derived exosomes play critical roles in all stages of tumor development and metastasis of almost all cancer types. Exosomal proteins may serve as biomarkers for clinical applications, still to be validated. Please reword the next sentence. Not clear. Exosomes extracellular gather in urine, thus becoming a great resource for recovery of biomarkers and a promising non-invasive diagnostic instrument for renal disease. Liquid biopsies (body fluids) may be preferable to tumor tissue biopsies since they are less invasive. Urinary exosomes in particular are available in great quantity in a noninvasive way and are representative of each of the cells of the urinary tract. In the present review, we summarize our knowledge of the urine exosomes with a new vision as liquid biopsy and high-throughput techniques. The emerging metabolic signature of urinary exosomes is also discussed in terms of its potential clinical application.