Detecting and monitoring colorectal cancer in blood

Liquid biopsies are gaining traction in identifying patients harboring cancers. The analysis of circulating extracellular vesicles (EVs or  “exosomes”) in particular, is a promising approach, as these vesicles are abundant, stable, and carry biomolecules of parent cells. Most EV assays, however, have lengthy sample workups and limited throughput, which often make them unsuitable for routine clinical use.

In a current study published in Nature Biomedical Engineering, investigators from CSB reported a high-throughput EV assay, HiMEX (high-throughput integrated magneto-electrochemical extracellular vesicle), that integrates EV enrichment and sensing. The HiMEX assay is complete within one hour and performed directly on plasma samples. The investigators further developed a high-throughput device compatible with a 96-well plate format and capable of parallel measurements. Using plasma samples from patients with colorectal cancer or healthy volunteers, the authors identified a panel of biomarkers (EGFR, EpCAM, CD24, GPA33) in circulating EVs that, when combined, showed higher diagnostic accuracy (>96%) than conventional serum markers.

In a prospective cohort, the combined biomarker profile enabled assigning patients to a high- or a low-risk 5-year disease-free survival group, and the serial monitoring of EVs during therapy showed that the burden of tumor EVs declined after surgery, but increased upon relapse. The HiMEX assay could be particularly useful in hospital environments where same day diagnosis in hundreds of samples is often necessary.