Blood test that can spot cancer without biopsy
A SIMPLE blood test for cancer could find tumours in the body without the need for a painful biopsy.
Scientists behind a new study hope so-called ‘liquid biopsies’ will revolutionise cancer treatment by distinguishing between people with slow-growing tumours and those most in danger.
The test involves two processes. The first, found by previous research, detects cancer in the body by finding dying tumour cells in the blood. The second process, revealed in this latest study, pinpoints the tumour’s location – by identifying normal cells killed off by cancer. These cells release DNA – with its own unique signature – into the bloodstream.
Combining both signals can provide a positive match for a specific cancer.
The team from the University of California, San Diego found DNA patterns for ten types of tissue – liver, intestine, colon, lung, brain, kidney, pancreas, spleen, stomach and blood.
It means cancer patients who have symptoms common to different types of cancer, such as bloating or sudden weight loss, could be diagnosed more quickly and easily. A biopsy is traditionally used to remove some tissue from a specific organ doctors want to test, which can be intrusive and painful for the patient.
The researchers, whose study was published in the journal Nature Genetics, screened individuals with and without tumours, looking for signals of the cancer mark-
‘Effective early detection’
ers and the tissue- specific DNA patterns. Senior author Kun Zhang, a bioengineering professor at the UC San Diego Jacobs School of Engineering, said: ‘We made this discovery by accident.
‘Initially, we were taking the conventional approach and just looking for cancer cell signals and trying to find out where they were coming from. But we were also seeing signals from other cells and realised that if we integrate both sets of signals together, we could actually determine the presence or absence of a tumour, and where the tumour is growing.’
The simple blood test offers rapid diagnosis, before cancer starts to spread through the body. Professor Zhang added: ‘ Knowing the tumour’s location is critical for effective early detection.
‘This is a proof of concept. To move this research to the clinical stage, we need to work with oncologists to further optimise and refine this method.’ Dr Catherine Pickworth, Cancer Research UK’s science information officer, said: ‘A biopsy can be invasive and unpleasant to go through, while any operation with an anaesthetic is risky.
‘This is potentially safer if it can be effective, which is why people are focusing on liquid biopsies.
‘Finding new ways to detect cancer at an early stage is vital to help more people survive the disease.
‘Looking for the DNA of cancer cells in the blood is an exciting idea, and this encouraging new approach might help reveal the location of tumours.’
But she added: ‘Before this can be turned into reality, we’ll need to see if it can effectively detect cancer and whether it could help doctors diagnose cancer at an earlier stage.’