The potential of liquid biopsies

The discovery of genetic alterations which are responsible for the development and progression of NSCLC led to the identification of a new generation of molecular biomarkers. However, in NSCLC, it is often difficult in clinical practice to obtain sufficient tumor material for genetic analyses. Therefore, analyses of tumor-specific genetic alterations in the serum or plasma of the patients are particularly valuable because they can provide temporal measurements of the total tumor burden as well as identify specific mutations that arise during therapy. The procedure of taking blood samples to detect tumor-specific genetic alterations is termed ‘liquid biopsy’. In particular, it can be used for a variety of clinical and research applications, including response assessment in epidermal growth factor receptor (EGFR)-mutated NSCLC patients receiving EGFR tyrosine kinase inhibitor therapy. It has been demonstrated that liquid biopsy is a fast and easy way to obtain information on tumor burden and assess the changes of the molecular nature of a tumor during the course of therapy. However, because of the limited amount of tumor material in the blood and yet insufficient knowledge of specific cancer biomarkers, extensive research has to be continued in this field to implement this method into clinical routine.

Only recently the potential of exosomes isolated from the bloodstream of cancer patients as novel biomarkers was identified. Exosomes are membrane- encapsulated vesicles containing different types of nucleic acids and proteins from the cell they originate from, thereby operating as information carriers between cells. Owing to the fact that exosomes deliver information both to their close environment and to distant organs, they are detectable in many biological fluids, for example, blood, thus making them easily accessible for research. (read more…)

Key Points

  • Liquid biopsy comprises a set of blood-based analyses to assess tumor-specific genetic alterations, therapy response, and resistance development.
  • cfDNA consists of small fragments of nucleic acids that are not associated with cells or cell fragments.
  • CTCs represent intact, viable tumor cells that can be purified from blood.
  • Exosomes are extracellular vesicles that contain nucleic acids, proteins, and metabolites.
Buder A, Tomuta C, Filipits M. (2015) The potential of liquid biopsies. Curr Opin Oncol [Epub ahead of print]. [abstract]

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