Breast cancer spreads to the brain by disguising itself as neurons

Share this article:
Finding keys to drug therapy resistance in glioblastoma
Finding keys to drug therapy resistance in glioblastoma

Often, several years can pass between the time a breast cancer patient successfully goes into remission and a related brain tumor develops. During that time, the breast cancer cells somehow hide, escaping detection as they grow and develop.

Breast cancer cells disguise themselves as neurons, becoming "cellular chameleons," found the scientists from City of Hope in Duarte, California. This allows them to slip undetected into the brain and then develop into tumors. The discovery is being heralded as "a tremendous advance in breast cancer research."

Although breast cancer is a very curable disease—with more than 95% of women with early-stage disease surviving after 5 years—breast cancer that metastasizes to the brain is difficult to fight. Only about 20% of patients survive 1 year after diagnosis.

"There remains a paucity of public awareness about cancer's relentless endgame," said Rahul Jandial, MD, PhD, a City of Hope neurosurgeon who headed the breast-cancer-and-brain-tumor study, published in the Proceedings of the National Academy of Sciences (2014; doi:10.1073/pnas.1322098111).

"Cancer kills by spreading. In fact, 90% of all cancer mortality is from metastasis," Jandial said. "The most dreaded location for cancer to spread is the brain. As we have become better at keeping cancer at bay with drugs such as herceptin, women are fortunately living longer. In this hard-fought life extension, brain metastases are being unmasked as the next battleground for extending the lives of women with breast cancer."

He added, "I have personally seen my neurosurgery clinic undergo a sharp rise in women with brain metastases years—and even decades—after their initial diagnosis."

Jandial and other scientists wanted to explore how breast cancer cells cross the blood-brain barrier—a separation of the blood circulating in the body from fluid in the brain—without being destroyed by the immune system.

The researchers' hypothesis was that,  given that the brain is rich in many brain-specific types of chemicals and proteins, perhaps breast cancer cells that could exploit these resources by assuming similar properties would be the most likely to flourish. These cancer cells could deceive the immune system by blending in with the neurons, neurotransmitters, other types of proteins, cells, and chemicals.

Taking samples from brain tumors resulting from breast cancer, the scientists found that the breast cancer cells were exploiting the brain's most abundant chemical as a fuel source. This chemical, gamma-aminobutyric acid (GABA), is a neurotransmitter used for communication between neurons.

When compared with cells from nonmetastatic breast cancer, the metastasized cells expressed a receptor for GABA, as well as for a protein that draws the transmitter into cells. This allowed the cancer cells to essentially masquerade as neurons.

"Breast cancer cells can be cellular chameleons (or masquerade as neurons) and spread to the brain," Jandial said.

He added that further study is required to better understand the mechanisms that allow the cancer cells to achieve this disguise, and he hopes that, ultimately, unmasking these disguised invaders will result in new therapies.

Share this article:
You must be a registered member of ONA to post a comment.

Sign Up for Free e-newsletters

Regimen and Drug Listings

GET FULL LISTINGS OF TREATMENT Regimens and Drug INFORMATION

Bone Cancer Regimens Drugs
Brain Cancer Regimens Drugs
Breast Cancer Regimens Drugs
Endocrine Cancer Regimens Drugs
Gastrointestinal Cancer Regimens Drugs
Genitourinary Cancer Regimens Drugs
Gynecologic Cancer Regimens Drugs
Head and Neck Cancer Regimens Drugs
Hematologic Cancer Regimens Drugs
Lung Cancer Regimens Drugs
Other Cancers Regimens
Rare Cancers Regimens
Skin Cancer Regimens Drugs

More in Web Exclusives

Improved tyrosine kinase inhibitor (TKI) selectively activates in tumor tissue, minimizing side ...

A new strategy developed by an interdisciplinary team of researchers aims to reduce the side effects connected to use of tyrosine kinase inhibitors (TKIs).

Prior cancer exclusion criteria may stymie potential of lung cancer clinical trials

A history of prior cancer can exclude many individuals from participation in clinical trails related to lung cancer, even when the prior cancer is unlikely to interfere with treatment outcomes.

Better adherence to guidelines for safe handling of antineoplastic drugs is needed

Recommended safe handling practices for workers who administer antineoplastic drugs in health care settings are not always followed, according to a new study.