New findings from research conducted by scientists at The Institute of Cancer Research, London, regarding certain types of advanced estrogen receptor (ER) positive breast cancers and their resistance to hormone therapy.
Scientists discovered that in 4% of patients, mutations in the estrogen receptor gene (ESR1), specifically mutations called F404, lead to significant resistance to a hormone therapy called fulvestrant. This resistance occurs when F404 mutations combine with specific pre-existing mutations in the ESR1 gene.
The research showed that cancer cells with these F404 mutations remained responsive to a set of compounds currently under clinical trials. This finding suggests that these new drugs could offer effective treatment options for patients whose cancers have developed resistance to fulvestrant.
The study proposes the use of blood tests to identify patients at risk of developing resistance through F404 mutations. By detecting these mutations early, patients could be offered alternative treatments before their cancer becomes resistant to current therapies.
The research involved analyzing blood samples from participants in the plasmaMATCH clinical trial. This trial uses liquid biopsies to study small traces of cancer DNA in the blood, which allows for the detection of genetic mutations associated with cancer and its response to treatment.
Fulvestrant is a common hormone therapy for ER-positive breast cancer, used either as an initial treatment or after other drugs fail. However, many patients eventually develop resistance to it.
The findings could lead to a more personalized approach to treating breast cancer, utilizing simple blood tests to tailor treatments to individual patients’ genetic profiles. This approach aims to overcome drug resistance and improve outcomes for patients with advanced ER-positive breast cancer.
Professor Nicholas Turner and Dr. Kotryna Temicinaite emphasized the importance of these discoveries in understanding treatment resistance and the potential to use alternative treatments for better patient outcomes. Dr. Nisharnthi Duggan highlighted the broader impact of such research in developing more effective treatment options for breast cancer.
This research marks a significant step towards understanding and combating resistance to hormone therapy in ER-positive breast cancer, offering hope for more effective treatments based on genetic testing and the development of new drugs.