Drugs that block the CCR5 receptor on cells—such as HIV med Selzentry (maraviroc)—may also help prevent aggressive breast cancers from spreading and causing lethal disease, according to new research conducted at Kimmel Cancer Center of Thomas Jefferson University in Philadelphia and published in a recent issue of Cancer Research.

“These results are dramatic,” said Kimmel researcher and lead author Richard Pestell, MD, PhD, in an accompanying news announcement. “[They] suggest it may prove to be a viable adjuvant therapy to reduce the risk of metastasis in the basal breast cancer subtype.”

CCR5 is found on immune system cells, including CD4 cells. While the exact role of CCR5 in normal immune function isn’t entirely understood, it is believed to play a role in sparking the immune system’s helpful—and potentially harmful—inflammatory response to infections.

CCR5 is a receptor for at least three chemical messengers, or chemokines, in the body, one of which is called CCL5 (or RANTES). HIV research, conducted about 20 years ago, found that CCL5-occupied CCR5 receptors slowed HIV infection of CD4 cells, a discovery that helped lead to the development of Selzentry. More recently, scientists have been focusing on the interaction between CCL5 and CCR5 as it relates to certain cancers.

The research conducted by Pestell and his colleagues helps confirm that CCR5 is found on the cells of basal breast tumors—cancerous growths that do not express androgen or estrogen receptors or the HER-2 protein and are generally difficult to manage—and that CCL5 prompts the cancerous cells to spread to other tissues in the body. And according test tube and rodent studies conducted by the researchers, Selzentry is one CCR5 antagonist that may potentially block the process, including the spread of basal cancer cells to the lungs.

“Our preclinical studies provide the rational basis for studying the use of CCR5 antagonists as new treatments to block the dissemination of basal breast cancers,” Pestell said.

These findings, the researchers added, may also have implications for other cancers where CCR5 promotes metastasis, such as prostate and gastric cancers.