Scientists at our research centre have shown that a new blood test can accurately identify the type of breast cancer tumour, and track changes over time. The test means people could be matched to the correct treatments at an earlier stage - and more treatments will be available to some.
In this section
Professor Nicholas Turner and his team at the Breast Cancer Now Toby Robins Research Centre at The Institute of Cancer Research, London presented their new findings at the San Antonio Breast Cancer Symposium, the largest breast cancer research meeting in the world.
The results provide further evidence of the growing promise of blood tests to help guide treatment for people with metastatic breast cancer. And the researchers believe this technology could be used for other cancers in the future.
Switching subtypes
There are many different types of breast cancer including oestrogen receptor (ER) positive, HER2-positive, and triple negative breast cancer.
When breast cancer spreads, it can switch type. For example, it could switch from ER-positive, HER-2 negative breast cancer to triple negative breast cancer. This happens in around 20% of metastatic (or secondary) tumours and is a major reason that treatment stops working.
To tackle this issue, the team developed a blood test called a Breast Circulating Methylation Assay (BCMA), which can track a cancer’s type over time and pick up if it has changed.
Looking at things in a new way
The blood test looks for tiny amounts of cancer DNA released into the blood stream by cancer cells, also known as circulating tumour DNA (ctDNA).
Using machine learning, the researchers designed and developed their test to pick up markers on the ctDNA that are specific to each of the main breast cancer types ER+/-, HER2+/-, and triple negative breast cancer.
In total, they analysed 191 blood samples from 86 people. And to check the accuracy of the blood test, the samples were compared with two tissue biopsies that were taken, on average, more than 5 years apart.
They found that breast cancer type switched in 19% of these samples. And the new blood test was almost 90% accurate at identifying this switch.
In 8% of the samples, tissue biopsies showed that the cancer had switched type, but the blood test showed that both types of breast cancer were present at the same time. This means people could potentially benefit from drugs specific to both types of breast cancer, expanding treatment options.
In addition, 29% of the tissue samples that were HER2-negative showed up as HER2-positive in the blood test – indicating that more people may benefit from HER2-positive specific therapies than currently receive them.
Our research is the first to show that it is possible to identify breast cancer’s type from a blood test – meaning that any changes to this type can be tracked easily over time, and treatment can be altered if necessary.
Professor Nicholas Turner
What's next?
This research lays the foundation for better monitoring of breast cancer’s response to treatment. The scientists hope that this test will ensure people receive effective treatments sooner, and they believe this technology could be used for other cancers in the future.
While we need further research and clinical trials before this test can be used in routine care, these early results are hugely promising. We’re incredibly proud to have funded this work, building a future where painless tests help to quickly choose the best treatments and give people with breast cancer more time to live and live well.
Dr Simon Vincent, chief scientific officer at Breast Cancer Now
This research was presented at the San Antonio Breast Cancer Symposium and was funded by Breast Cancer Now, Wellcome Trust, and Cancer Research UK.
Pioneering research into liquid biopsies
Professor Nicholas Turner and his team at the Breast Cancer Now Research Centre at the Institute of Cancer Research, London, have been pioneering research into the use of liquid biopsy blood tests to detect breast cancer relapse and guide treatment for more than a decade.