A team of researchers led by Dr Nicole Verrills has been investigating if a new ‘gene marker’ can predict which breast cancer patients may have poorer treatment outcomes. They have also identified a potential new treatment option for these patients.
Breast cancer is the number one cancer affecting Australian women, with around 3,000 people dying from the disease each year. Survival rates have increased dramatically over the last two decades, but the 5-year survival of patients whose breast cancer has metastasised, or spread,
is only 23%.
A big challenge with breast cancer is that it is not just one disease – in fact there are several different subtypes of breast cancer. ‘Luminal B’ breast cancer accounts for around 21% of all breast cancers and is linked to treatment resistance and poor survival. There is no accurate way of identifying which women have this type of breast cancer.
Dr Verrills and her team have discovered a key mechanism that makes some breast cancers more aggressive and resistant to standard treatments. In particular, her research has been exploring the association between the gene PPP2R2A and Luminal B breast cancer. The team has discovered that breast cancer cells become more aggressive when this gene is missing. The cells also become resistant to standard therapies. This suggests patients who have lost this gene will have a worse outcome from their cancer compared to those with an intact PPP2R2A gene.
Importantly, Dr Verrills has discovered that breast cancer cells with this gene marker are sensitive to a drug that is already in clinical use for other diseases. These drugs can not only effectively kill these cells, but can also re-sensitize the tumour to standard treatment. The team is now working towards validating their findings in preclinical testing.
Dr Verrills and her team are now looking at how testing for the PPP2R2A gene could be used as a diagnostic tool. When a woman is first diagnosed with breast cancer, she could be tested for this gene. If found to be missing the PPP2R2A gene, this would indicate she is likely to be resistant to traditional therapies and needs an alternative treatment.
The team has also found that breast cancers with low PPP2R2A levels could be highly sensitive to a certain type of chemotherapy. If more preclinical testing confirms these results, this chemotherapy could be introduced into clinical trials for patients who have low PPP2R2A levels offering hope for patients with treatment resistant breast cancer.