Sanford Barsky M.D., a well-known breast cancer researcher, and a team of other scientists have published a journal article relating the transgenic mammary tumors of mice to human breast cancer. The complex study, entitled “Pten in stromal fibroblasts suppresses mammary epithelial tumours” explores the findings of Barsky and his team. These findings have important implications for future breast cancer research.
The key focus of the article is on the role of connective tissue in the tumor’s surrounding environment, or “microenvironment” and the resulting pathways connecting the two. The connection between the tumor microenvironment and the development of cancer is incredibly complex and there is a knowledge gap in the science community about why connective tissue is so integral to the cancerous tumors.
The “Pten” referred to in the article title is the name of a gene that is known by scientists to suppress the growth of tumors. This gene is found in fibroblasts, or connective tissue cells, which are in the human mammaries. Unfortunately, this gene disappears or is deleted and the connective tissue changes, gaining more blood vessels that supply blood to the growing tumor. When Pten is deleted, mammary tumor growth in mice rapidly increases, the study found.
A similar observation is made in the connective tissue of women with breast cancer, indicating that the pathway referred to in the article signals changes in gene expression in both humans and mice. Gene expression itself is reliant on a process called “transcription” that essentially reads the information on a strand of DNA. In the study, Pten interacts with a transcription factor named “Ets2”. The two components were found to be critically important to Pten’s ability to curb growth in mammary epithelial tumors.
Strangely, as noted in the study, when Pten is deleted and Ets2 remains active, tumor growth is still initiated. However, when Ets2 is deactivated the tumor microenvironment was altered enough that the tumor was unable to continue its accelerated growth. The relationship between Pten and Ets2, referred to as the “Pten-Ets2 axis”, is specific to the tumor stroma and is the key finding of the study.
The findings of this study could prompt other scientists to discover ways to enable the Pten-Ets2 pathway and suppress the growth of mammary tumors. It is not a cure for breast cancer, but it is certainly on the right path. By preventing the tumor cells from spreading and creating an unfavorable environment for their growth, breast cancer can be more easily contained and far less devastating. Breast cancer patients can have tumors removed without fear that they will return.
If scientists can find a way to manipulate the pathway in this way, it would change the way breast cancer is treated. This discovery is significant, but the practical use of these findings is still in the distant future.
by Carolyn Littmann