The Origin of Tumor DNA in Urine of Urogenital Cancer Patients: Local Shedding and Transrenal Excretion

Abstract

In urogenital cancers, urine as a liquid biopsy for non-invasive cancer detection holds great promise for future clinical application. Their anatomical position allows for the local shedding of tumor DNA, but recent data indicate that tumor DNA in urine might also result from transrenal excretion. This study aims to assess the origin of tumor-associated DNA in the urine of 5 bladder and 25 cervical cancer patients. Besides natural voided urine, paired urine samples were collected in which contact with the local tumor was circumvented to bypass local shedding. The latter concerned nephrostomy urine in bladder cancer patients, and catheter urine in cervical cancer patients. Methylation levels of GHSR, SST, and ZIC1 were determined using paired bladder tumor tissues and cervical scrapes as a reference. Urinary methylation levels were compared to natural voided urine of matched controls. To support methylation results, mutation analysis was performed in urine and tissue samples of bladder cancer patients. Increased methylation levels were not only found in natural voided urine from bladder and cervical cancer patients, but also in the corresponding nephrostomy and catheter urine. DNA mutations detected in bladder tumor tissues were also detectable in all paired natural voided urine as well as in a subset of nephrostomy urine. These results provide the first evidence that the suitability of urine as a liquid biopsy for urogenital cancers relies both on the local shedding of tumor cells and cell fragments, as well as the transrenal excretion of tumor DNA into the urine.

Urine biomarkers in cancer detection: A systematic review of preanalytical parameters and applied methods

“…It was shown that ctDNA could be detected in both plasma and urine of patients with progressive disease and could be used to predict disease recurrence 32,33 . Recently it was shown that ctDNA from urothelial cancer in urine can also result from direct shedding in the urine present in the bladder, as well as excreted via glomerular filtration 11 …”

“…6 Despite the lack of understanding about how DNA crosses the renal barrier, several studies have shown the presence of transrenal cfDNA in urine for different physiological and pathological conditions, such as pregnancy, cancer and inflammation. 5,6,8,10,11 Recent studies showed that cell-free nucleic acids and tumor DNA are shed into the circulation and pass the renal barrier to be excreted in urine. 12,13…”

Advances in early detection methods for solid tumors

“…After the release of cfDNA from cells during tumor cell necrosis or apoptosis, its DNA molecules cross the renal barrier after entering the circulatory system and are subsequently detected in urine samples (Botezatu et al, 2000;Hentschel et al, 2021). Similarly, cfDNA in urine samples can be isolated and detected in urine through centrifugation or a sizebased selection method.…”

Urine as a Source of Liquid Biopsy for Cancer

“…While several reviews have been published on urine as a source of liquid biopsy for cancer, most of them have mainly focused on genitourinary cancers. Chen et al focused on urine liquid biopsy technologies and its use in cancer, glomerular disease, and tuberculosis [21], while Yu et al focused on prostate and bladder cancer [22], and Hentschel et al on bladder, prostate, and cervix cancer [23]. This review seeks to highlight the components of urine liquid biopsy and its utility and limitations in oncology, mainly in non-urological cancers.…”