New liquid biopsy could help identify advanced breast cancer patients who would benefit from a change in treatment

A novel blood test that measures genetic changes in circulating cancer DNA could help identify patients with metastatic breast cancer who could benefit from a change of treatment, new research has found.

Researchers funded by Cancer Research UK and Breast Cancer Now at the University of Leicester and Imperial College London demonstrated that a single blood test could detect and track alterations in 13 different genes, including some of the most important drivers of breast cancer such as the ERBB2 gene (HER2).

The study, published in the journal Clinical Chemistry, was led by Dr David Guttery and Professor Jacqui Shaw in our Department of Cancer Studies.

The test – one of a number of ‘liquid biopsies’ in development – can identify acquired changes to HER2 in patients with secondary breast cancer, indicating that HER2-targeted therapy, such as Herceptin, could be offered.

The test also detects mutations in the ESR1 gene (oestrogen receptor), which has been linked to resistance to anti-hormone therapies such as aromatase inhibitors. Patients with this mutation could be eligible for a change of treatment to chemotherapy or other selective oestrogen receptor therapies such as fulvestrant (Faslodex).

This is the first time researchers have been able to analyse two types of acquired DNA mutation – called point mutations and copy number alterations (CNAs) – in a single blood test. However, further validation is needed to confirm its usefulness before any such test can be rolled out into the clinic.