An international research team, including QIMR, has found that an enzyme in triple-negative breast cancers makes the cancer less responsive to chemotherapy, opening the door for new treatments.
QIMR’s Professor Mark Smyth said the research had shown that high levels of the enzyme known as CD73 predicted a poorer response to chemotherapy and worse survival in triple-negative breast cancer.
“We’ve discovered that CD73 – an enzyme that sits on the surface of cancer cells and produces the immune suppressive molecule, adenosine – is often present in high quantities in this subtype of breast cancer. And when you block it, chemotherapy is much more successful,” Professor Smyth said.
“Identifying this new target could have a major impact on the disease. It provides a concrete path for the development of new treatments.”
Human trials of inhibitors of CD73 could begin within five years.
This study, co-led by Dr John Stagg from the University of Montreal, looked at breast cancer samples from 6000 women across the world. It found that there was more CD73 in TNBC than in other types of breast cancer, and that it was more likely to be present in cases where breast cancer spread, or metastasised.
“What’s more, CD73 made the cancer more resistant to traditional chemotherapy treatments,” Professor Smyth said.
“There is an urgent clinical need for new treatment options for triple-negative breast cancer because of its poor survival rates; we’re confident we’ve identified a new target.”
About 15 per cent of breast cancers are described as triple-negative. This means the cancer doesn’t have any of the three hormone or growth factor receptors usually found on breast cancer cells. Triple-negative breast cancer (TNBC) usually affects younger women and has the poorest survival rates because it has an increased risk of spreading through the body.
This research also involved breast cancer clinician researcher, Sherene Loi, from the Peter MacCallum Cancer Centre in Melbourne. It was funded by the NHMRC and the Susan G Komen Foundation, USA.
It is published in the current online issue of PNAS (USA) and can be viewed at http://www.pnas. org/.