Milk Protein Found In Breast Cells Triggers Aggressive Cancer
December 28, 2012

Milk Protein Found In Breast Cells Triggers Aggressive Cancer

Lawrence LeBlond for - Your Universe Online

Health advocates for years have told us that milk does the body good. Health experts have also been keen on promoting the positive effects breastfed milk has on childhood development. But now, milk is getting a bad rap--particularly, a certain protein found in breast milk is the problem.

Scientists have recently discovered that this protein, called ELF5, which is found in all breast cells and is responsible for milk production, is the main cause behind the worsening of breast cancer in women. When the protein tries to trigger milk production and cancer cells do not respond, the cancer will become more aggressive.

The finding could have important implications and open up new opportunities for treatment of the deadliest form of cancer in women.

“The discovery opens up new avenues for therapy and for designing new markers that can predict response to therapy,” said lead author Professor Chris Ormandy from the Garvan Institute of Medical Research in Sydney, Australia.

Ormandy is known for his earlier research where he discovered that ELF5 was the main driver in milk production. In the new research, published today in the journal PLoS Biology, he and his colleagues took the research a step further and found the link between ELF5 and aggressive breast cancer.

“Cancer cells can't respond properly (to ELF5), so they ... acquire some characteristics ... that make the disease more aggressive and more refractory (resistant) to treatment with existing therapies,” Ormandy said in a telephone interview with Reuters Health´s Tan Ee Lyn.

For their study, Ormandy and colleagues grew human breast cancer tissues in the lab and genetically manipulated them to contain higher amounts of ELF5. They watched as the petri dish samples responded aggressively to the higher concentrations of ELF5.

Breast cancer cases account for 23 percent of all cancers in women and 14 percent of cancer deaths. Before doctors can decide on a treatment plan for their patients, they need to find out if the cancer has receptors for the hormones estrogen and progesterone, which, in the case of breast cancer patients, promote growth in tumors. Two-thirds of breast cancers are usually positive for estrogen receptors, which require anti-hormonal therapies that lower estrogen levels or block estrogen from supporting cancer growth. For the remaining third of patients, their cancers do not have receptors, which mean they will not benefit from hormonal therapies. In these patients, other treatments such as chemotherapy are needed.

Ormandy and his team found that cancers with the receptors had low levels of ELF5, while those without the receptors had significantly higher levels of the protein.

“What we have shown in this paper is high ELF5 tumors are dependent on ELF5 for their proliferation and if we block ELF5 in high ELF5 tumors, we will block proliferation and that will treat the tumor,” Ormandy said. “If we can develop a drug that targets ELF5, it will be very useful for that group of women.”