Scientists part-funded by Breast Cancer Now have developed a new highly sensitive blood test to deliver precision medicine to women with BRCA mutations who have breast or ovarian cancer.

Thursday 2 November 2017      Research
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The test detects changes in the BRCA1 or BRCA2 genes that mean the cancer will no longer respond to platinum chemotherapy or targeted drugs called PARP inhibitors.

In future, it could be used to monitor women treated with these drugs so that those who begin to resist treatment can be switched to alternative therapies as early as possible, before the cancer starts to progress.

Scientists funded by the Mary-Jean Mitchell Green Foundation at the Breast Cancer Now Toby Robins Research Centre at The Institute of Cancer Research, London, used the new test, known as a ‘liquid biopsy’, to analyse blood samples from 24 women who had an inherited fault in one of the cancer risk genes BRCA1 or BRCA2.

They found DNA changes to allow tumours to resist treatment in the blood of four out of 19 women with ovarian cancer, and of two out of five with breast cancer – 21 per cent and 40 per cent, respectively.

In four out of six of the women who developed resistance mutations, the tumour DNA contained more than one change – suggesting that cancer finds multiple different ways to resist targeted drugs.

Baroness Delyth Morgan, Chief Executive at Breast Cancer Now, which helped to fund the study, said:

“That this test could detect drug resistance in cancer patients with BRCA1/2 mutations at such an early stage is highly exciting.

“Drug resistance remains a major barrier to stopping more women dying from breast cancer. Yet this innovative method could enable the ‘real-time’ tracking of a patient’s response to treatment, allowing doctors to swiftly change therapies that women won’t benefit from and spare them any unnecessary side-effects.

“Through liquid biopsies, we hope to begin outsmarting breast cancers – with treatment choices guided not by surgical knives or biopsy needles, but by the wealth of information in a small amount of blood.

“We now eagerly await a large clinical trial, in the hope this liquid biopsy will bring us closer to tailoring treatment to patients’ tumours in the clinic, ensuring everyone is given the best possible chance of survival.”

Professor Nicholas Turner, Professor of Molecular Oncology at The Institute of Cancer Research, London, and Consultant Medical Oncologist at The Royal Marsden NHS Foundation Trust, said:

“With this new liquid biopsy, we picked up changes in tumour DNA that could give us early warning if a woman’s cancer is likely to stop responding to treatment.

“Next, we aim to further evaluate the blood test as part of a large clinical trial. Our study also opens up further research into how to stop cancer evolving to become resistant to targeted drugs.

“In the future, this liquid biopsy could help us pick out those women with breast or ovarian cancer who are most likely to benefit from targeted therapy, and offer alternative treatment to women as soon as they develop drug resistance.”

The study, largely funded by Breast Cancer Now in the UK – thanks to generous support from the Mary-Jean Mitchell Green Foundation, and published today (Thursday) in the journal Clinical Cancer Research, was carried out in collaboration with researchers at the Memorial Sloan Kettering Cancer Center in New York.