Genetic “Off-Switch” for Aggressive Form of Breast Cancer Found

           About 15% of all breast cancer patients are diagnosed with triple-negative breast cancer.  Triple-negative breast cancer got its name because the cells test negative for estrogen receptors, progesterone receptors, and HER2 receptors.  Since triple-negative breast cancer lacks these receptors, it cannot be targeted by any drugs that are available for the treatment of other types of breast cancer.  Triple-negative breast cancer patients typically have shorter survival rates than patients who are affected by other forms of breast cancer.

Researchers from Sydney’s Garvan Institute of Medical Research have identified a gene known as inhibitor of differentiation 4 (ID4).  They discovered that ID4 is an indication of an aggressive form of triple-negative breast cancer.  The researchers determined that ID4 may also be responsible for controlling the aggressive form of triple-negative breast cancer.  The researchers found that high levels of ID4 are produced in about half of all triple-negative breast cancers.  They found that cases in which ID4 was present had poor prognoses.  Through experimentation with models of triple-negative breast cancer, the scientists were able to show that blocking the ID4 gene caused the tumor cells to stop dividing.  The researchers discovered that the more benign form of triple-negative breast cancer appears to originate from specialized cells while the aggressive form appears to originate from stem cells.

Previous studies have shown that breast stem cells are an integral part of breast growth and development during puberty and pregnancy.  This study has demonstrated that ID4 is responsible for whether or not the breast stem cells develop into specialist cells.  The researchers were able to demonstrate that blocking ID4 in a breast stem cell activates genes that drive cell specialization, estrogen receptors, and other genes that are expressed by forms of breast cancer that are less aggressive.  The researchers are hopeful that by blocking ID4 in the aggressive form of triple-negative breast cancer, they will be able to treat it with tamoxifen.  Tamoxifen is the drug that is used to treat estrogen receptor-positive breast cancers.

            I found the results of this study remarkable.  I think the findings of this study will provide a lot of hope for those who are diagnosed with triple negative breast cancer.  Hopefully future studies involving the investigation of ID4 will provide further understanding of how to treat triple-negative breast cancers.