Liquid Biopsy, Key for Precision Medicine

Sequencing Circulating Tumor DNA Can Provide a More Complete Molecular Picture

The last 10 years have seen enormous progress in both the understanding of cancer as a disease, as well as the development of targeted therapies, with an unprecedented number of new drugs approved for cancer treatment by the FDA and EMA. The availability of a large set of targeted therapies has created the need for efficient molecular profiling of patients.

A decade ago, the term “liquid biopsy” was coined to describe diagnostic procedures carried out to detect molecular biomarkers found in the blood or in other bodily fluids (e.g., urine or cerebrospinal fluid) of patients.

Blood, and potentially any other bodily fluid, contains cancer-derived elements that allow the molecular characterization of the disease, contributing to early diagnosis, accurate prognosis, personalized therapeutics, and disease monitoring. Materials derived from tumors include circulating tumor cells (CTCs), circulating tumor DNA (ctDNA), as well as RNA, protein markers, and extracellular vesicles, such as exosomes.

When a tumor cell dies, it releases DNA molecules from its fragmented genome into the bloodstream. These nucleic acids in the blood can be purified and analysed using PCR-based methods, next generation sequencing (NGS), or array technologies. Data generated from analysing liquid biopsies have shown the enormous potential in this approach that could have a revolutionary impact on clinical practice. During the last few years, several studies have shown that key cancer mutations can be detected in liquid biopsies, mirroring those detected in traditional tumor biopsies.

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