Irish scientists have discovered a potential new approach to treating triple negative breast cancer, which is currently one of the most difficult forms of breast cancer to treat.

The research was led by scientists from BREAST-PREDICT - a country-wide collaboration between breast cancer experts that is funded by the Irish Cancer Society. Working in collaboration with an EU-funded research consortium called RATHER, the scientists found that a new drug called THZ-1 can prevent the growth of triple negative breast cancer.

Around one in five women who develop breast cancer are diagnosed with this form of the disease and it is more often found in younger women. This is an aggressive type of breast cancer that lacks three important proteins or biomarkers in the cells of the tumour - oestrogen receptor, progesterone and HER2.

As a result of this, patients cannot receive so-called targeted therapies such as Herceptin or hormone therapy (Tamoxifen). The only effective treatment is chemotherapy, and while many patients do respond to this, treatment resistance is a common problem.

Those who are treatment resistant have a poor prognosis and their tumours are more likely to return and spread after initial treatment. As a result, the need for new treatment options is urgent.

The research focused on a protein called CDK7, which was found to be present at high levels in patients with this type of cancer. Those with high levels were more likely to experience a relapse after chemotherapy, which means that this protein could be used as a biomarker to identify those unlikely to respond well to this treatment.

The researchers noted that this testing for CDK7 means that doctors could prioritise those less likely to respond to chemotherapy. However, they also tested the drug THZ-1, which acts on CDK7. They found that breast cancer cells grown in the laboratory saw their growth halted when treated with this drug, both on its own and in combination with other treatments.

The scientists proposed THZ-1 as a potential treatment option for triple negative breast cancer, especially when working in combination with existing treatments.

"This study has uncovered an important new treatment possibility for patients with triple negative breast cancer, a particularly aggressive subtype of the disease. This success was only possible through a concerted team-based approach from multiple national and international collaborators," commented the study's lead investigator, Prof William Gallagher, who is professor of cancer biology at UCD.

Further research is needed before this treatment can be used on patients, however this marks a key step in opening up a wider range of options for patients with this difficult-to-treat cancer.

Details of these findings are published in the journal, Cancer Research.