THE SPREAD of triple-negative breast cancer may be greatly reduced by utilising an existing class of drugs that has been approved for the treatment of oestrogen receptor-positive breast cancer, the most common form of breast cancer, a new study has revealed.
In the USA, breast cancer is the second most common cancer among women, with approximately 252,710 new cases and 40,610 deaths from the disease predicted for 2017. Triple-negative breast cancer comprises 10–20% of all breast cancer cases. While it is possible to treat oestrogen receptor-positive, progesterone receptor-positive, and HER2-positive breast cancer by targeting oestrogen, progesterone, and HER2 receptors, respectively, with hormonal therapies and other medications, in triple-negative breast cancer the cancer cells do not have oestrogen, progesterone, or HER2 receptors. This means they do not respond to such therapies and medications, making it challenging to treat in patients. Indeed, the current study confirmed these findings.
CDK 4/6 inhibitors are one such class of drugs currently approved for the treatment of oestrogen receptor-positive and HER2-positive breast cancers, that have previously been found to be ineffectual in reducing the growth of cancer cells in triple-negative breast cancer. However, this study discerned that CDK 4/6 inhibitors had the potential to halt the spread of cancer cells to other body areas in triple-negative breast cancer. Researchers discovered this by testing CDK 4/6 inhibitors across several triple-negative breast cancer models, such as immunodeficient mouse models implanted with tumour tissue from humans. The mechanism of action is believed to be that CDK 4/6 inhibitors target a protein named SNAIL, which plays a role in the promotion of cancer metastasis.
Commenting on the importance of their findings, co-author Dr Matthew Goetz, Mayo Clinic, Rochester, Minnesota, USA, announced: “These findings may provide a new treatment for the prevention of cancer metastasis. Mayo Clinic is now developing new studies that will focus on the role of CDK 4/6 inhibitors and their potential to inhibit cancer metastasis in women with triple-negative breast cancer who are at highest risk for cancer metastasis.”