Key protein stops breast cancer spread

A discovery by La Trobe University breast cancer researchers could spare some women from having unnecessary treatment.

Researchers from the La Trobe Institute for Molecular Science, in collaboration with the Garvan Institute of Medical Research in Sydney, have identified key proteins that prevent breast cancer from spreading beyond the breast duct.

Approximately 25 percent of Australian breast cancer patients are diagnosed with ‘ductal carcinoma in situ’ (DCIS). This type of breast cancer starts in the breast duct, where it is surrounded by myoepithelial cells, which act as a barrier.

However, seven percent of DCIS cancer will break through the myoepithelial cells and spread.

Drs Belinda Parker and Hendrika Duivenvoorden from La Trobe University, in collaboration with Professor Sandra O’Toole at the Garvan Institute, have discovered that the composition of myoepithelial cells may be a critical determining factor in breast cancer progression.

Dr Parker’s research team have identified a cancer suppressor protein, known as stefin A, that enhances the ability of the myoepithelial cells to act as a barrier, essentially trapping the disease in the breast duct.

“Myoepithelial cells are the barrier that breast cancer cells encounter before they spread through the breast tissue and enter the blood stream,” Dr Duivenvoorden said. “When this happens, the risk of cancer spreading to other parts of the body is increased.”

Dr Belinda Parker said results from laboratory tests have been promising.

“By modelling early-stage breast cancer in the laboratory using tissues donated from patients, we have identified a key function of this protein in blocking the invasive behaviour of cancer cells,” Dr Parker said.

She said the discovery could help specialists predict which DCIS patients are likely to develop invasive cancer, allowing them to provide individualised care.

“Without a way to identify those cases that will spread beyond the breast duct, surgery and radiotherapy is currently the predominant treatment option,” Dr Parker said.

“Women experience fear and uncertainty when they are diagnosed with breast cancer. Being able to determine the likelihood of cancer spread in DCIS will help specialists and patients make more informed decisions about treatment.”

Professor O’Toole commented: “Now that we understand more about the biology of DCIS and how it progresses to an invasive cancer, we can work on developing better diagnostic tests and a more personalised approach to treatment.”

(Source: La Trobe University, The Journal of Pathology)