Researchers find blood test to identify rare breast cancer mutations

13 December 2019 (Last Updated December 13th, 2019 12:50)

Researchers from Cancer Research UK have found that a blood test could quickly identify rare mutations in patients with advanced breast cancer.

Researchers find blood test to identify rare breast cancer mutations
Human breast cancer cells. Credit: Min Yu.

Researchers from Cancer Research UK have found that a blood test could quickly identify rare mutations in patients with advanced breast cancer.

Under the plasmaMATCH clinical trial, researchers found the test can detect traces of DNA shed by tumours into the bloodstream.

The research team at The Institute of Cancer Research, London and The Royal Marsden NHS Foundation Trust evaluated blood from over 1,000 women with advanced breast cancer.

Contrary to standard tissue biopsies, the blood test could facilitate physicians to deliver effective treatments to patients as researchers found specific weaknesses in breast cancer DNA that could be targeted with drugs.

In the UK, nearly 55,200 breast cancer cases are diagnosed annually.

Currently, genetic defects in patients with advanced breast cancer are identified by taking out a piece of the tumour using a biopsy or surgery. However, this invasive process is time-consuming and these defects can also change after treatment.

Furthermore, in advanced cancer, it is difficult to take further biopsies, given that the disease would have spread to other parts of the body.

The research team studied if a blood test could identify rare mutations in three genes called HER2, ESR1 and AKT1 that drive breast cancer.

The team used the information on the mutations and divided 142 patients into four treatment groups, with each group being given targeted therapies to combat the particular nature of cancer.

Out of the 20 women with HER2 mutation, five responded to the targeted treatment of neratinib and three out of 18 with the AKT1 mutation responded to medication with capivasertib. However, the therapy targeting the ESR1 mutation was not sufficiently effective.

Researchers later checked tissue samples from the patients to validate their findings and confirmed that liquid biopsy had accurately detected mutations in over 95% of cases.

The Institute of Cancer Research molecular oncology professor Nicholas Turner said: “We have now confirmed that blood tests can quickly give us a bigger picture of the mutations are present within multiple tumours throughout the body, getting the results back to patients accurately and faster than we could before.”