Redesigning testing for high-risk childhood leukaemia

Background

Acute lymphoblastic leukaemia (ALL) is the most common cancer in children and a leading cause of death from disease. After initial treatment, up to one in five children with ALL will eventually relapse and half of these patients will not survive.  

To identify which children are at high risk of relapse, clinicians collect bone marrow samples to check for any remaining residual ALL cells. This is called minimal residual disease testing, or MRD testing. Children identified as being at high risk of relapse can then receive more intensive treatment to improve their chances of survival, while children at low risk can be spared additional treatment, reducing the short- and long-term impact of side effects. 

However, MRD testing currently uses bone marrow collected and repeated sampling is an invasive procedure. While this approach is very effective, it cannot detect any residual ALL cells and or predict relapse in any other organs in the body. 

The research

Professor Lock and his team have been investigating a less invasive and more broadly effective approach to identifying children at high risk of ALL relapse to replace bone marrow sampling. If cancer cells are still present in the body after treatment, then DNA from the tumour cells will be circulating in the patient’s blood and can be detected by a technique known as liquid biopsy. Detecting very small quantities of this DNA before cancer relapse is a challenge.  

To overcome this challenge, Professor Lock and his team have joined forces with UNSW Chemist Professor Justin Gooding, who has developed an ultrasensitive technology called a ‘dispersible electrode biosensor’, capable of detecting even the smallest amounts of tumour DNA in blood. 

In this project, the multidisciplinary team will use this technology to study the dynamics of tumour DNA that is specific for each patient in blood through the cycle of ALL progression – diagnosis, remission and relapse.  

This research will pave the way for the team to develop less invasive and personalised diagnostic tests to detect residual ALL cells still present after treatment.  

The impact

This project is the starting point for implementing personalised blood testing to identify children at high risk of relapse from ALL. This ground-breaking new testing approach will lead to improved detection of the smallest of traces of cancer left behind after treatment. As the blood test is minimally invasive, clinicians will be able to test more frequently, allowing them to monitor for changes and personalise ongoing treatment options in real-time.  

The ‘dispersible electrode biosensor’ can be used to detect traces of any solid tumour. Once Professor Lock and his team have successfully developed this new diagnostic approach, it could be applied to other cancers in children and adults.