US – A team of scientists from the American Institute Duke Cancer have identified in mice a molecular key cells that cause breast cancer to invade the bone marrow, where they are protected from chemotherapy and hormonal therapies to be able to eradicate them, after which they can reappear years later.

Experts have discovered how to overcome this tactic dissimulation, which not only prevents cancer cells which are hidden inside the bones, but allows it to be incorporated into the bloodstream where they can be destroyed.

This discovery, published in the journal Science Translational Medicine, provides insights into one of the most devastating tendencies of some cancers, the ability to resurface after once considered cured.

The researchers hope that this development, if confirmed by further tests in animals and humans, could lead eventually to new therapies to treat breast cancer.

Dorothy A. Sipkins, principle of investigator from the Duke Cancer Institute, said that clinical studies indicate that breast cancer can be caught early and treated and patients may not have symptoms of the disease. However, a decade or fifteen years later, can suffer a relapse and very often the site of cancer is metastatic bone.

Sleeper cells may resurface later

Researchers in the study described how those cells possessing breast cancer hormone receptor positive roam through the blood and tissues of mouse looking for some blood vessels in the bone marrow containing a molecule called E-selectin. They find them using their “molecular key” to link to the E-selectin and so cancer cells find their way into the spongy tissue inside bones where often remain dormant.

In human patients these sleeper cells may resurface later and cause a relapse of metastatic cancer for which there is no cure, explained Sipkins.

Bone marrow biopsies in patients with breast cancer have shown that, even in very early stages of the disease, cancer cells move from the chest to the bone marrow.

According to the expert now we know how they get in and also have identified a “major mechanism”, in mice, on how the cells remain anchored in the bone marrow. This which may provide new ways to intervene at the molecular level before the sleeper cells take hold and cause a relapse.

Sipkins is hopeful that by understanding how these cells breast cancer migrate through the body and knowledge of their life cycle can help discover ways to make them more vulnerable and treatable. To do so, she hopes to go ahead with additional testing in mice to better understand the approach of experts before going on to perform human studies.