Presence of Urinary Exosomes for Liquid Biopsy of Clear Cell Renal Cell Carcinoma: Protocol for a Pilot Feasibility Study

Abstract

Background Approximately 70%-80% of kidney cancers are clear cell renal cell carcinomas (CCRCCs). Patient management is based on imaging (abdominal ultrasound and computerized tomography), surgical excision of the tumor, and pathological analysis. A tissue biopsy is therefore necessary to confirm the diagnosis and avoid unnecessary nephrectomy. For metastatic cancers, a tissue biopsy is essential for establishing the targeted therapy. This biopsy of tumor material is invasive and painful. Other techniques such as liquid biopsy would help reduce the need for tissue biopsy. The development of a simple biological test for diagnosis is essential. CA9 is a powerful marker for the diagnosis of CCRCC. Exosomes have become a major source of liquid biopsy because they carry tumor proteins, RNA, and lipids. Urine is the most convenient biological liquid for exosome sampling. Objective The aim of this study (PEP-C study) is mainly to determine whether it is possible to detect urinary exosomal CA9 for the molecular diagnosis of CCRCC. Methods This study will include 60 patients with CCRCC and 40 noncancer patients. Exosomes will be isolated from urine samples and exosomal CA9 will be detected by transmission electron microscopy, flow cytometry, and reverse transcription-quantitative polymerase chain reaction. Results This study is currently underway with funding support from the CHU Saint-Etienne of France. Conclusions We expect to demonstrate that urinary tumor exosomes could be a novel liquid biopsy to diagnose CCRCC and to guide clinicians in treatment decision-making. Trial Registration ClinicalTrials.gov NCT04053855; https://clinicaltrials.gov/ct2/show/NCT04053855 International Registered Report Identifier (IRRID) DERR1-10.2196/24423

Role of tumor-derived exosomes in metastasis, drug resistance and diagnosis of clear cell renal cell carcinoma

“…found five novel mRNAs specific for stage I ccRCC in urinary exosomes, namely NME2, AAMP, CAPNS1, VAMP8, and MYL12B ( 70 ). In addition, a pilot study on the development of a reliable technique to detect exosomal CA9 in the urine of CCRCC patients for molecular diagnosis of CCRCC is underway in France ( 71 ).…”

Importance and implications of exosomes in nephrology and urology

“…Oncosomes, which are present in body fluids at high concentrations [ 114 ], have been described extensively as structures of prognostic and diagnostic value [ 14 , 34 ]. They can be extracted and analyzed regarding their embedded nucleic acids and proteins by performing liquid biopsies which have previously been used as a less invasive tool for the detection of biomarkers like circulating tumor cells (CTCs) [ 56 ].…”

“…Recently, some independent studies demonstrated that specific exo-miR might serve as promising agents for the diagnosis and monitoring of RCC [ 56 , 100 , 108 ] (NCT04053855). Wang et al and Zhang et al found that the expression of serum-derived circulating exo-miR-210 in patients with ccRCC was significantly elevated which was associated with metastasis and poor prognosis, and in turn levels significantly decreased within the first week after surgical tumor resection.…”

“…The heterogeneous content of exosomes, their high stability, the protection of the cargo through a liquid bilayer, and their function in intercellular communication has led to a strong interest in pursuing their utilization for diagnosis, prognosis, carriers of vaccines, and therapy of different diseases with a large focus on cancer [ 56 , 81 , 109 ].…”

Urine-based liquid biopsy: a new avenue for the management of renal cell cancer

“…Some commercial kits for isolation of urinary exosomes have been available. Besides the new markers such as cirRNAs, the markers already found in tumor tissues are also possible paths to be explored in liquid biopsy in future (22). The isolation method of urinary exosomes suitable for clinical laboratory use remains the main challenge.…”