Subscribe to the BioNews newsletter for free

Advanced Search

Search for

Like the Progress Educational Trust on Facebook



Tumour gene tests produce conflicting results

19 December 2016

By Isobel Steer

Appeared in BioNews 882

A study has cast doubts on the reliability of 'liquid biopsies' – blood tests that detect tumour mutations and are increasingly used to guide treatment.

'Our findings indicate that the output from genetic testing can differ markedly depending on which test is applied,' the researchers wrote in JAMA Oncology. This can lead to different treatment recommendations, depending on which test was used.

The research was led by Professor Anthony Blau of the University of Washington and Dr Sibel Blau, a clinical oncologist. Patients were given two simultaneous tests – traditional tissue biopsy and novel liquid biopsy.

The researchers compared two liquid biopsies – FoundationOne and Guardant360. FoundationOne tests tumour tissue for 343 genes. Guardant360 tests blood to examine 70 genes in the cell-free circulating tumour DNA (cfDNA). Each test costs around $5800.

'With a tumor biopsy, it's like you read the book cover to cover. With a liquid biopsy, you read an entire shelf of books, but you only read the dust jackets,' Dr Justin Odegaard, the senior medical director of Guardant Health, told The Atlantic.

The tests identified 45 mutations in total within the patient group. But only 10 mutations (22 percent) were discovered by both platforms. This meant that the tests gave different drug recommendations to the majority of patients.

The new study only tested nine patients, but the findings match other work. A paper from researchers at Northwestern looking at liquid versus tissue biopsies reported that over half of the mutations found by one test did not show up in the other.

Which test is more accurate? 'There is no easy answer,' Dr Richard Schilsky, the chief medical officer of the American Society of Clinical Oncology, told The Atlantic. 'Because nobody actually knows what is the truth in terms of what's happening inside a person's tumor throughout the body.'

Dr Sibel Blau added that she thinks liquid biopsies 'are not really ready for primetime' and that clinicians should rely on tissue biopsy results until there is more research on the effectiveness of liquid biopsies.  

GenomeWeb | 15 December 2016
JAMA Oncology | 15 December 2016
The Atlantic | 15 December 2016
Medical Xpress (Press release) | 15 December 2016


13 March 2017 - by Dr Loredana Guglielmi 
Researchers have developed a new blood test that can not only detect cancer at an early stage, but can also indicate where the tumour is located in the body...
06 March 2017 - by Matthew Thomas 
Dr Kat Arney leads a fascinating and wide-ranging discussion of genetic testing – from testing for cancer genes to whether your child's DNA can predict their future sporting ability...

12 September 2016 - by Meetal Solanki 
A blood test costing only £35 could help in the early diagnosis of oesophageal cancer and could be available in five years' time...
09 November 2015 - by Kirsty Oswald 
Researchers have identified the genetic mutations that drive resistance to the hormone therapy abiraterone in patients with advanced prostate cancer...
09 November 2015 - by Ayala Ochert 
Scientists say it may be possible to track the progress of cancer – and cancer treatment – in real time from fragments of tumour DNA that are shed into the bloodstream...
14 September 2015 - by Isobel Steer 
A US startup called Pathway Genomics has launched the first commercial 'liquid biopsy' to identify cancerous mutations via a blood test...
14 April 2014 - by Simon Hazelwood-Smith 
A genetic test has been developed to predict the likelihood of prostate cancer returning after treatment. The test looks for 'genetic signatures' often found in recurring cancers...

Be the first to have your say.

You need to or  to add comments.

By posting a comment you agree to abide by the BioNews terms and conditions

- click here to enquire about using this story.

Published by the Progress Educational Trust


Public Conference
8 December 2017

Speakers include

Professor Azim Surani

Professor Magdalena Zernicka-Goetz

Professor Robin Lovell-Badge

Sally Cheshire

Professor Guido Pennings

Katherine Littler

Professor Allan Pacey

Dr Sue Avery

Professor Richard Anderson

Dr Elizabeth Garner

Dr Andy Greenfield

Dr Anna Smajdor

Dr Henry Malter

Vivienne Parry

Dr Helen O'Neill

Dr César Palacios-González

Philippa Taylor

Fiona Fox

Sarah Norcross

Sandy Starr


Good Fundraising Code

Become a Friend of PET HERE and give the Progress Educational Trust a regular donation