Summary
Detecting tumour DNA in blood to diagnose or monitor cancer non-invasively.
In depth
Circulating tumour DNA fragments (ctDNA) carry tumour mutations; detection monitors response, relapse and screens for cancer. Sensitivity is limited for early-stage disease.
Detection uses digital PCR or deep sequencing for tumour-specific mutations or methylation. Tracks minimal residual disease after surgery. Multi-cancer early detection tests are being evaluated.
Example: ctDNA falling after treatment suggests response.
A liquid biopsy analyses blood or other fluids for traces of tumours, mainly circulating tumour DNA (ctDNA), circulating tumour cells and exosomes. ctDNA fragments are short, released by dying cells, and carry the tumour's mutations or methylation patterns.
Uses include choosing therapies by finding actionable mutations, monitoring response and detecting minimal residual disease or early relapse before scans can see it, and prenatal screening from cell-free fetal DNA. Sensitivity is limited in early-stage disease because little DNA is shed.
Example: rising ctDNA after surgery predicts that cancer will return.
Frequently asked questions
What is Liquid Biopsy?
Detecting tumour DNA in blood to diagnose or monitor cancer non-invasively.
Which area of biology covers Liquid Biopsy, and how advanced is it?
Liquid Biopsy is one of the 56 topics in Biotechnology & Genomics. It is rated Advanced, so it suits learners who want specialist depth. Related topics in this area include Personalised Medicine, Proteomics, DNA Fingerprinting.
Why does Liquid Biopsy matter?
It is less invasive than tissue biopsy and can be repeated often.
Can you give an example of Liquid Biopsy?
Non-invasive prenatal testing uses cell-free fetal DNA in maternal blood.
What should I learn before Liquid Biopsy?
Work through the Beginner topics in Biotechnology & Genomics first, such as Biotechnology, Genetic Engineering, Selective Breeding, then return to Liquid Biopsy. Advanced topics assume the Intermediate vocabulary.
What topics are related to Liquid Biopsy?
The closest topics to Liquid Biopsy are Personalised Medicine, Proteomics, DNA Fingerprinting, Single-Cell Sequencing. Comparing them side by side is a good way to see how the ideas connect.
How can I check that I understand Liquid Biopsy?
Read the summary and the in-depth section, then use the quick check on the interactive lesson for Liquid Biopsy. To practise the whole of Biotechnology & Genomics, use the Biotechnology & Genomics quiz.
How is Liquid Biopsy different from Personalised Medicine?
Liquid Biopsy: Detecting tumour DNA in blood to diagnose or monitor cancer non-invasively. Personalised Medicine: Tailoring treatment to a patient's genetic profile, for example in pharmacogenomics. Read both side by side and note what each one explains.
How should I study Liquid Biopsy step by step?
First, read the summary and write the definition in your own words. Second, read the in-depth section and note any example. Third, compare it with Personalised Medicine and explain the difference aloud. Finally, take the Biotechnology & Genomics quiz and come back to this page for any question you miss.