Even low-androgen triple-negative breast cancer responds to anti-androgen therapy

A University of Colorado Cancer Center study published today in the journal Molecular Cancer Therapeutics shows that only about 1 percent of triple-negative breast cancer cells in a tumor must be "androgen-receptor-positive" to show benefit from anti-androgen therapies. There are no FDA-approved targeted therapies for triple-negative breast cancer. Clinical trials currently underway are showing promising preliminary results of anti-androgen-receptor therapies against triple-negative breast cancers expressing a higher percentage of androgen-receptor-positive cells.

"What we're showing is that the threshold for benefit from anti-androgen-receptor therapies in triple-negative breast cancer may be far lower than we previously thought. This is an extremely optimistic finding for many people who have been without options for targeted cancer therapy," says Valerie Barton, the study's first author and PhD candidate in the lab of CU Cancer Center investigator Jennifer Richer, PhD.

Triple-negative breast cancers are those without known hormone or genetic drivers - specifically, breast cancers that do not drive their growth with the hormones estrogen or progesterone, or with the gene HER2. Without a known driver, there has been no "target" in triple-negative breast cancer to treat with targeted therapies, and the triple-negative subtype has the worst five-year survival rate of any breast cancer. The current study is the most recent in an extremely promising line of work at the CU Cancer Center and elsewhere that aims to prove androgen receptors as an additional driver and target in breast cancer

"We're getting closer to being able to call some triple-negative breast cancers, androgen-receptor-positive breast cancers. And we may have to start referring to the remaining triple-negative breast cancers that are completely without androgen receptors as quadruple-negative breast cancers," Barton says.

Did You Know…

Black women are twice as likely as white women to develop tumors referred to as being “triple negative.” This is a highly aggressive form of cancer which affects one third of black women who are diagnosed with breast cancer. It is highly aggressive because the targeted therapies currently used to treat the other forms of breast cancer are not as effective in treating triple negative breast cancer.
Within all age categories and all stages of the disease, black women are more likely to die of breast cancer than women of other races.
A growing body of evidence suggests that breast cancer is different biologically in black women.
Low-income black women lack access to quality and appropriate mammography screening.
Even when fully insured, black women often receive unequal treatment and care.