June 20, 2012
A subset of triple-negative breast cancers contains a genetic change that contributes to cancer growth and may be possible to target with drugs. These results were published in Nature.
Targeted therapies are anticancer drugs that interfere with specific pathways involved in cancer cell growth or survival. Some targeted therapies block growth signals from reaching cancer cells, others reduce the blood supply to cancer cells, and still others stimulate the immune system to recognize and attack the cancer cells. Depending on the specific “target,” targeted therapies may slow cancer cell growth or increase cancer cell death.
In order to identify targeted therapies that may be effective for a particular type of cancer, it’s important to understand the factors that drive the cancer. A study recently published in the journal Nature sought to identify genetic changes that may contribute to certain types of breast cancer, including triple-negative breast cancer. The study collected tumor samples from 103 breast cancer patients from Mexico and Vietnam. The DNA from the tumor samples was compared with DNA from normal tissue.
A genetic change that was identified in a triple-negative sample involved a fusion of two genes: MAGI3 and AKT3. The protein produced by this fusion gene is thought to contribute to cancer growth. When the researchers looked for this fusion gene in another set of tumor samples, they found it in 7% of triple-negative samples (5 out of 72).
Drugs that target this biological pathway are already being investigated for other purposes, and may eventually prove to be useful for triple-negative breast cancers that contain the fusion gene. If researchers are able to find a targeted drug that is effective against these cancers, it would be an important advance in the treatment of triple-negative breast cancer. Only a subset of triple-negative breast cancers contain the genetic change identified in this study, but ongoing research may identify additional targets.