Liquid Biopsy: The Cutting Edge of Clinical Chemistry?

By Jane Cook
September 9, 2021

In light of the ongoing trial of Elizabeth Holmes, the founder of the failed diagnostic start-up Theranos, it is prudent to ask: what new advances have managed to succeed in minimally invasive, blood-based diagnostics?

Liquid Biopsies

The hottest topic in this area is cancer profiling via liquid biopsy. Liquid biopsies conta genetic (and epigenetic) biomarkers in the blood that are used to identify tumor cells. The most well-established application of liquid biopsy relies on the fact that cancer cells or their DNA will end up circulating in the blood.

The two main methods involve identifying biomarkers either in circulating tumor cells in the blood (CTCs) or in cancer DNA fragments in the blood, known as cell-free DNA (cfDNA). These methods, though promising, are still extremely challenging to optimize for reliable results and translation to the clinic.

Challenges arise in first, identifying which biomarkers are indicative of a given tumor’s disease stage, severity and location, and figuring out whether or not they are present in the blood. Furthermore, a single biomarker can only reveal a limited amount of information: the most accurate tumor profiles from liquid biopsy use the cumulative effects of many biomarkers.

Another challenge is the current variety of assays of liquid biopsies and what they can detect. Targetable mutations like KRAS or BRAF genes are detected in both CTC and cfDNA assays while transcriptional changes like upregulation of a given gene can only be detected in CTCs.

The solution to these challenges lies in custom software engineering and bioinformatics pipeline development. Algorithms are needed to create synergy between the data from different assays and to weigh the effects of the different biomarkers on how reliably they can identify an aspect of a certain tumor.

Though there is much research to be done, liquid biopsies hold promise for improving the cancer patient experience by using less invasive tests and achieving earlier diagnoses and interventions. The challenges in this technology provide huge opportunity for innovation in bioinformatics and genomic data analysis.

Jane Cook, Journalist & Content Writer, Bridge Informatics

Jane is a Content Writer at Bridge Informatics, a professional services firm that helps biotech customers implement advanced techniques in management and analysis of genomic data. Bridge Informatics focuses on data mining, machine learning, and various bioinformatic techniques to discover biomarkers and companion diagnostics. If you’re interested in reaching out, please email or


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