Urine as a biological modality for colorectal cancer detection

ABSTRACT

Introduction: The increasing incidence of colorectal cancer (CRC) in young adults warrants early and preferably noninvasive diagnostic modalities. Although the current stool-based assays have had good performance indicators for CRC detection, the overall poor uptake remains a challenging issue. However, alternative blood and urine markers are emerging.

Areas covered: This paper discusses the various urinary biomarkers available for the detection of CRC. The more commonly encountered drawbacks are the small number of studies and the size of the study population. We discuss the role of microRNA and ProstaglandinE2 in CRC detection. The emergence of new, low-cost technologies, specifically in the detection of volatile organic compounds (VOCs), presents a promising future. We postulate possible mechanisms for the origin of these VOCs in urine and their role in carcinogenesis.

Expert opinion: Urinary biomarkers provide an alternative option to the stool-based screening tests. MicroRNA and ProstaglandinE2 have shown utility in CRC detection. Evidence so far suggests that VOCs could also be a potential biomarker for the detection of CRC. In addition to its interaction within the colon lumen, this altered ‘VOC signature’ might also play a role in carcinogenesis. Low-cost technology may enable such diagnostic methods to be utilized at the point of care.

KEYWORDS:

• Colorectal cancer
• urine volatile organic compounds
• urinary biomarker
• microbiome
• tryptophan metabolism, volatile organic compounds mechanism

Article Highlights

• There have been various urinary biomarkers described in the literature, but their utility in day-to-day clinical practice is yet to be established.

• Whilst urinary biomarkers have variable performance for the detection of CRC, the genetic markers appear to exhibit higher tissue specificity; the evidence for PGE2 suggests that this may be useful for both CRC and adenoma detection. However, larger and more robust studies are needed to validate these findings.

• Urine VOCs have become an attractive biomarker in recent years. As a result of emerging technologies, we are now able to detect these compounds and characterize them in detail at a relatively low cost.

• Mechanistic origins are discussed as VOCs are not only products of a complex interaction between the microbiome and colonic cells but also appear to play a role in carcinogenesis and rapid growth of the tumor.

Declaration of Interest

The authors have no relevant affiliations or financial involvement with any organization or entity with a financial interest in or financial conflict with the subject matter or materials discussed in the manuscript. This includes employment, consultancies, honoraria, stock ownership or options, expert testimony, grants or patents received or pending, or royalties.

Reviewers Disclosure

Peer reviewers on this manuscript have no relevant financial relationships or otherwise to disclose.

Additional information

Funding

This paper was not funded.