Irish Cancer Society researchers discover potential new way to treat aggressive type of breast cancer
Research led by Irish scientists based in UCD and RCSI has found a potential new approach to treating one of the most difficult-to-treat forms of breast cancer, which currently has limited treatment options.
Scientists from BREAST-PREDICT, an Irish Cancer Society Collaborative Cancer Research Centre, in collaboration with an EU-funded research consortium called RATHER, have shown that a new drug, called THZ-1, can prevent the growth of triple negative breast cancer. Their findings have recently been published in the journal Cancer Research.
Triple negative breast cancer affects approximately 1 in 5 women diagnosed with breast cancer, and is more often diagnosed in younger women. This aggressive subtype lacks three important proteins or biomarkers in the tumour cells, namely estrogen receptor, progesterone receptor and HER2. This means that patients with this type of breast cancer cannot receive ‘targeted therapies’ such as hormone therapy (e.g. Tamoxifen) or Herceptin.
Instead, the only effective treatment for these patients is chemotherapy, making this type of cancer one of the most difficult to treat.
Although many of these patients do respond well to chemotherapy, resistance of the tumour to this treatment is a common problem. Patients with resistant disease have a poor prognosis, and their tumours are more likely to return and spread following treatment. Doctors and researchers are urgently looking for new treatment options for these patients.
This most recent study focused on a protein called CDK7, which the researchers found to be present at high levels in triple negative breast cancers. Interestingly, patients with high levels of CDK7 present in their tumour were more likely to experience a disease relapse following standard chemotherapy treatment. This means that high CDK7 levels could be used as a ‘biomarker’ to identify patients unlikely to respond well to chemotherapy. This type of test could be very useful to their doctors, as they could then prioritise these patients for a more aggressive treatment regime.
The researchers also tested a drug that acts on CDK7, called THZ-1, to investigate if this could be a novel treatment for triple negative breast cancer. Remarkably, treating triple negative breast cancer cells grown in the laboratory with THZ-1 halted their growth, both on its own and in combination with other treatments. The researchers proposed THZ-1 as a novel treatment option for this aggressive cancer type, particularly in combination with existing treatments, to improve their success rate.
Commenting on the findings, Prof William Gallagher, the lead investigator on the study and Professor of Cancer Biology at UCD, said: “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.”
This study was supported by the Irish Cancer Society Collaborative Cancer Research Centre BREAST-PREDICT and the EU-funded RATHER project, an international research consortium focused on tackling difficult-to-treat subtypes of breast cancer; both of which are co-ordinated by Prof. Gallagher. While further research is needed on this novel treatment before it can be used in breast cancer patients, this work is a key step in opening up a wider range of new and less toxic treatment options for triple negative breast cancer patients.
Head of Research at the Irish Cancer Society, Dr Robert O’Connor, hailed the development as a significant milestone in the ongoing work of BREAST-PREDICT: “This paper highlights the vital work which the Irish Cancer Society invests in through the generous support of the public. As Director of BREAST-PREDICT, Prof Gallagher has been pivotal in overseeing the work of more than 50 breast cancer researchers, funded by generous donations to the Irish Cancer Society. Through his leadership, BREAST-PREDICT is making huge strides in breast cancer research, making new discoveries about these cancers which will potentially lead to more ways to prevent, detect and treat the disease and ensure more cancer survivors live longer, happier lives.”