Australian researchers have identified new markers and treatment targets for women with breast cancer in a $5 million study funded by the National Breast Cancer Foundation.
Breast cancer is the most common invasive cancer in Australian women, with more than 13,500 Australian women diagnosed each year, and more than 2680 women dying from the disease.
The study compared the activity of a group of proteins called nuclear receptors (NRs) in normal breast tissue and tumours, and involved 16 researchers from across Australia.
Currently, during a biopsy or surgery for breast cancer, a sample of cells is collected and tested for receptors, which helps determine the best treatment for the type of cancer.
It is hoped the discovery of these new receptors will help to better identify and more effectively treat different types of breast cancer.
The research team included Perkin's Professor Peter Leedman, who heads the Laboratory for Hormone Dependent Cancers at the Harry Perkins Institute of Medical Research and was led by Professor George Muscat from The University of Queensland's Institute for Molecular Bioscience (IMB) and Professor Christine Clarke from The University of Sydney's Westmead Millennium Institute.
Professor Clarke said examining the activity of nuclear receptors in 116 samples of normal breast tissue and tumours had produced several promising leads.
"We found two nuclear receptors that are overactive in breast tumours and five whose activity decreased as cell abnormality increased, all of which could serve as drug targets.
"The project also identified several nuclear receptors that act as markers, including four that are significant predictors of whether a patient who has been treated with tamoxifen will survive disease-free."
The team also found five nuclear receptors that could be used to accurately classify breast cancer types.
Professor Muscat said nuclear receptor proteins play vital roles in many processes in the body, including breast growth and development, and cancer growth.
"Aberrant Nuclear Receptor expression has been implicated in breast cancer, and the oestrogen receptor is already targeted by tamoxifen. Nuclear Receptors are well characterised drug targets for the treatment of many other human diseases. However, no one had systematically examined the entire family of 48 receptors to determine their role in breast cancer," he said.
"Our research has identified nuclear receptors that are relevant for women with breast tumours that don't respond to current drugs, giving hope to those patients who need it most."
The team will now work to define the molecular pathways through which the receptors influence breast cancer, the next step forward in developing treatments.