New research published in PLoS Biology finds a link between a protein essential for milk production and an increased metastasis of breast cancer. The protein in question appears to aid breast cancer’s advance through two separate pathways. Share on Pinterest ELF5 is a protein responsible for switching on milk production. It may also assist the spread of breast cancer. Breast cancer is the most common cancer to affect American women. In 2012, the Centers for Disease Control and Prevention (CDC) report that 224,147 women in America were diagnosed with breast cancer and 41,150 died as a result. Figures like these constantly fuel research into the mechanisms at work in breast cancer. How breast cancer begins and how it spreads are complicated questions we are only beginning to answer. Any new potential targets for drugs to attack are investigated thoroughly in the hope that more successful defenses can be built against this most prevalent of cancers. A recent study, carried out by the Garvan Institute of Medical Research in New South Wales, Australia, looks in detail at the mechanisms of a particular protein – ELF5.

ELF5 functions ELF5 is a transcription factor, and as such, it switches on targeted genes at certain times, in response to specific signals. ELF5 activates a number of genes, most of which are involved in epithelial roles. Importantly, for the purposes of this research, ELF5 is partly responsible for switching on mammalian milk production. During pregnancy, hormone changes drive the mammary glands to produce milk. The processes involved in this switch are complex and relatively unknown. However, ELF5 appears to be an important player. ELF5 drives certain cells to develop into milk-secreting alveolar cells in response to specific hormone levels. Research has shown that if mice are bred without ELF5, they do not grow a milk-secreting epithelium during pregnancy. Conversely, if ELF5 is over-expressed in virgin mice, they begin to express milk.

ELF5 and its role in breast cancer This most recent study, led by Dr. David Gallego-Ortega, investigates the role of ELF5 in cancerous breast tissue. The team observed that ELF5 switches from a life-nourishing role to that of a deadly rabble rouser. In response to a tumor, it recruits immune cells to surround the area and encourages the growth of new blood vessels. These new vessels become “leaky,” allowing cancer cells to escape into the blood and then the lungs. Once in the lungs, the tumor can fix itself and continue its harmful activities. Dr. Gallego-Ortega says: “We show that ELF5 drives the spread of breast cancer to the lungs in a model of breast cancer, and it also predicts early metastasis in patients with luminal A breast cancer.”