Dr Kotryna Temcinaite, Senior Research Communications Manager at Breast Cancer Now, said:
“Each year in the UK, around 55,000 women are diagnosed with breast cancer, and up to 80% of these cancers will be oestrogen receptor positive.
"In some cases, this type of breast cancer will spread to other parts of the body, becoming incurable secondary (metastatic) breast cancer.
"we urgently need to find new and effective treatments to stop women dying from this devastating disease.
“It is therefore very encouraging that this study has identified a new drug molecule called ErSO that shrinks oestrogen receptor positive breast cancer tumours in mice, including those that have spread to other parts of the body.
"It is also extremely exciting that this study suggests ErSO could be used to shrink secondary breast cancer tumours in the brain, as this is something most current breast cancer drugs cannot do.
“We hope that further research will confirm that ErSO is safe and effective for humans to use, without unwanted side effects so that it can benefit people with breast cancer in the future.
“Anyone looking for breast cancer information and support call our free Helpline on 0808 800 6000 to talk to one of our expert nurses.”