Liquid biopsy: The secrets in your blood
‘The secrets in your blood’ sounds like it could be a new detective novel but instead this post is about the use of blood in diagnostic tests, also known as liquid biopsies. Now diagnostic tests really are the bedrock of medicine. Analyzing the chemical makeup of saliva, blood or urine can show if you have allergies, anemia or even cancer. In fact, your very existence was most likely first confirmed through a pregnancy test, which is based on the principle of lateral flow.
The history of diagnostics goes way back. It’s pretty amazing that the principle of testing for glucose in urine for managing diabetes that was invented in early 20th century is still being applied today. At the start of 2020 Artificial Intelligence was shown to even outperform radiologists. There is no doubt that diagnostics are the past, present and future of better patient management.
The development of new in-vitro diagnostic tests (those which take place outside the body using blood or other fluids) rely on harnessing a wide range of biological principles. As the science around those techniques develop, this new knowledge will surely revolutionize how we diagnose and monitor disease.
Liquid biopsy will be a game changer for personalized medicine in cancer
Let’s look at how advancements in how we extract cell-free DNA (fragments of DNA from tumors that released to the blood plasma) from blood samples in the lab will help improve liquid biopsy tests and hopefully detect cancer earlier.
Mounting clinical data shows the advantages of testing blood or other bodily fluids to make a diagnosis. Liquid biopsies work by capturing and analyzing biomarkers, mostly cell-free DNA and have been shown to give more complete disease profile and make it easier to measure a condition over time.[1]
These tests have rapidly gained traction in recent years with applications in reproductive health, cancer and transplant medicine. Indeed, the global liquid biopsy market was valued at $1.5 billion in 2017.[2] Yet there are still barriers to overcome for the technique to be adopted broadly.
A key challenge is that blood only contains a limited amount of useful genetic material. Each sample is precious and so liquid biopsy test developers need to be able to recover the maximum amount of cell-free DNA from a small sample.
For now, tissue biopsies are still necessary to provide the complete picture of disease but as the understanding of cell free DNA in liquid biopsies increases, its use will surely expand beyond giving a yes/no diagnosis to determining recurrence risk and the exact order and combination of therapies needed to control or even cure advanced cancers. Let’s see how far the science progresses this year.
[1] https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6291575/ Accessed January 2020
[2] BCC Research 2017 ‘Liquid Biopsy Research Tools, Services and Diagnostics: Global Markets’ Page 13.
