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Teasing Apart Hope From Hype For Liquid Biopsy

April 24, 2019 | Liquid biopsies are emerging as rapid and cost-effective tools for the management of cancer patients, says Nicola Valeri, Reader in Gastrointestinal Oncology and Consultant Medical Oncologist at the Institute of Cancer Research and The Royal Marsden Hospital, UK.

A medical oncologist by training, Valeri is at a prime position to see the promise and hurdles of liquid biopsies in deciding and monitoring treatment in patients with cancers, including advanced metastatic colorectal cancer. He believes accelerating precision cancer medicine will rely on the potential of liquid and tissue biopsies, primarily based on the combination of different biomarkers improving overall patient selection.

On behalf of Diagnostics World News, Emily Le spoke with Valeri about the outcomes of liquid biopsy compared to tissue biopsy, how to know which combination of biomarkers to use for liquid biopsy, and more.

Editor's note: Emily Le, a conference producer at Cambridge Healthtech Institute, is planning a track dedicated to Clinical Applications of Circulating Biomarkers at the upcoming Molecular Diagnostics Europe Conference in Lisbon, Portugal, May 6-9. Valeri will be speaking on the program. Their conversation has been edited for length and clarity.

Diagnostics World News: How is liquid biopsy compared to tissue biopsy? Are there any studies that correlate the outcomes using these two types of diagnostics in parallel?

Nicola Valeri: A number of studies comparing tissue and liquid biopsies have been reported. Even though some technical issues related to the use of blood-based (liquid) biopsies have emerged, the feeling is that liquid biopsies may be more rapid and cost/effective than tissue biopsies. Furthermore, liquid biopsies may overcome issues related to tumor heterogeneity in tissues better capturing the complexity of cancer.

There are many types of biomarkers that are currently used for liquid biopsy such as cfDNA, CTCs, exosomes, platelets, extracellular vesicle, and many more. How do we know when to use what and which combination of biomarkers to use?

cfDNA appears as one of the most promising applications in the clinical setting; however other technologies might prove beneficial in understanding the metastatic dissemination (i.e. CTC and CTC clusters in breast cancer). Similarly, exosomes, vesicles and circulating microRNAs might help to understand crosstalk between cancer and stroma. I believe that all these technologies will be complementary at clinical and pre-clinical level in advancing the understanding of cancer biology and patient’s management.

The field of liquid biopsy is very crowded right now. How do we sniff out hope from hype?

From a clinical standpoint, prospective validation of different platforms in the context of clinical trials will help to understand the true potential of liquid biopsies in managing metastatic cancer patients or patients with minimal residual disease after an operation. Proving that adapting, escalating, or de-escalating treatment can improve patients’ outcomes and/or reduce toxicity from unnecessary treatments will help to prove the true potential of liquid biopsies in the clinic.