A team of scientists from UC Berkeley, UCSF and Boston College have found that triple-negative breast cancer tumors — a breast cancer subtype — rely on fat as an energy source, a discovery that has brought them one step closer to potentially developing a new type of therapy for this cancer.

Triple-negative breast cancer lacks expression of the three receptors — estrogen, progesterone and HER2 — which are commonly targeted in therapies used to treat breast cancer. According to Roman Camarda, graduate student at UCSF and contributing author of the study, out of the 200,000 women diagnosed with breast cancer per year, triple-negative breast cancer affects approximately 20 percent.

Andrei Goga, lead researcher of the study and professor of cell and tissue biology at UCSF, has noted that patients with this particular type of cancer have the worst prognosis of those diagnosed with breast cancer.

“For other types of breast cancer, there are pretty good drugs,” Goga said. “We really don’t have specific drugs for this triple-negative breast cancer.”

According to Camarda, the researchers learned that the tumors prefer to feed on fat, specifically. In order to target triple-negative breast cancer tumors directly, researchers must prevent the breakdown of fat in order to starve the tumor.

Triple-negative breast cancer tumors put more effort into breaking down fat molecules as opposed to building them up. Camarda said this discovery resulted from researchers paying close attention to the metabolism of the cancer, which had previously not been studied.

The team conducted the study by creating a model of triple-negative breast cancer and transplanting human patient tumors into mice to determine what processes metabolized the tumor.

Researchers found that when they prevented fatty acid oxidation, or the breakdown of fat, it stopped both the human patient tumors and model tumors from growing further, according to Goga in an email.

Meanwhile, researchers plan to test previously approved FDA drugs that inhibit fat from breaking down in order to allow them to develop a new therapeutic target for triple-negative breast cancer.

UC Berkeley professor of cell and developmental biology Gary Firestone, who did not participate in the study, said he sees a future to this research.

“The observations about potentially targeting triple negative breast tumors is very intriguing and has the potential to lead to the development of new anti-cancer strategies for various types of cancers,” Firestone said in an email. “Because of the cellular heterogeneity that can be observed within triple negative primary breast cancers, an important and interesting future direction will be to assess effectiveness and potential side effects in clinical trials.”

Goga said the research team hopes to start assembling a clinical trial within the next year.

According to campus associate professor of nutritional sciences and toxicology Daniel Nomura, senior author of the study, the team plans to use its research to potentially develop a therapy for this malignant form of breast cancer.

“There are a lot of women who die from triple-negative breast cancer” said Nomura. “We can save a lot of lives.”

Contact Kailey Martinez-Ramage at [email protected]