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Monitoring diffuse midline gliomas with liquid biopsies

Researchers have found a way to monitor diffuse midline gliomas (formerly known as DIPG) by measuring tumour biomarkers through a blood test

Researchers have found a way to monitor diffuse midline gliomas (formerly known as DIPG) by measuring tumour biomarkers through a blood test.

Biomarkers are essential to effectively manage brain tumours as they are a means of detecting the presence and progression of the disease.

A biomarker (or indicator) is any change in a cancer cell that can be analysed. These changes can range from DNA modifications to unique molecules produced by the cancer cell.

In order to identify biomarkers, a biopsy needs to be conducted. A brain biopsy is a procedure that consists of drilling a small hole in a person’s head to be able to reach and extract a part of the tumour.

Unfortunately, due to the location of certain tumours, such as diffuse midline gliomas, biopsies are not used to monitor the disease.

Diffuse midline glioma is a type of primary, high-grade brain tumour occurring in children. It is one of the most fatal paediatric brain tumours, with less than 1% of patients surviving beyond five years.

The dismal prognosis of diffuse midline glioma can be attributed to its location, the brain stem, a difficult to access region of the brain.

Unlike standard biopsies, liquid biopsies are minimally invasive. As the name implies, liquid biopsies analyse tumour biomarkers found in bodily fluids such as blood or cerebrospinal fluid, a liquid coating the brain and spinal cord.

In a recent study, researchers from UCSF Benioff Children’s Hospitals and Children’s National Health System, demonstrated the effectiveness of using liquid biopsies to monitor the disease in 48 children with diffuse midline gliomas.

The children underwent liquid biopsies that used blood and spinal fluid samples to detect any tumour DNA that was floating around.

The researchers were able to identify a mutation called, H3K27M (that drives tumour growth), in 42 of the 48 patients, a level accuracy comparable to a standard biopsy.

In addition, researchers also found that in 12 children who underwent liquid biopsies before and after radiation therapy, the amount of tumour DNA in the blood and spinal fluid had decreased, indicating the tumour had shrunk. This was later confirmed using an MRI in 10 of the 12 patients.

These are encouraging results, as this technology has the ability to allow clinicians to tailor treatments based on the changes found in an individual’s tumour and give real time updates of the treatment’s efficacy.