Researchers Map Metastatic Tumor DNA

Breast cancer is many different diseases with many causes and factors that influence how it develops and responds to treatment. Until scientists discover what causes breast cancer, we won't be able to prevent or cure it. A new Canadian research effort may prove to be an important step in the right direction.

Eight years after the first human genome was decoded, researchers have decoded and mapped the DNA of breast cancer, for the first time documenting how breast cancer evolves to invade tissue beyond the breast. The effort involved decoding three billion letters in the DNA sequence of an estrogen-positive metastatic tumor. In the process, scientists identified 32 different mutations that caused the tumor to spread, including five that had never before been linked to breast cancer.

This discovery is truly significant. For the first time, it shows that a metastasized breast cancer tumor is genetically different from the original tumor, and it provides a roadmap to show how this occurs. Currently, we have no cure for metastatic breast cancer; this new discovery provides an understanding that is a necessary first step to developing drugs that specifically target a tumor's genetic makeup. While the Canadian discovery doesn't provide all the answers, it does pave the way for further research to develop these new treatments.

October 16, 2009