Women who are under 40, African-American, or Hispanic are most at risk of triple-negative breast cancer, according to research published in the May 2007 issue of the journal Cancer. Around 15 percent of breast cancers are triple negative—lacking markers for estrogen receptors (ER), human epidermal growth factor receptors 2 (HER2), and progesterone receptors. Researchers identify these cancers as basal-like subtypes.
In the study, African-American women were at highest risk—their cancers were more likely to be diagnosed at a later stage and they had a five-year survival rate of only 14 percent. The comparable five-year rate was 36 percent for white women and 37 percent for Hispanic women with the same stage and receptor status cancer.
Scientists have previously speculated that breast cancer is biologically different in African American women, which may be why they are more likely to get one specific form of the disease. The fact that Hispanic women also tend to get triple-negative adds a new dimension to the issue, which may help narrow future research into what causes breast cancer in specific women, says Katrina Bauer, research scientist at the California Cancer Registry and lead researcher in the study. “We can no longer think of breast cancer as one disease,” she says.