A genetic variant in Hispanic women has been identified that may shield them from breast cancer.

The variant, known as a single-nucleotide polymorphism (SNP), originates from indigenous Americans and offers significant protection from breast cancer. In particular, they are protected from the more aggressive estrogen receptor–negative forms of breast cancer, which typically have a poor prognosis.

According to the Centers for Disease Control and prevention (CDC), breast cancer is the most common cancer in women in the U.S., and the most common cause of death from cancer among Latina women.

Senior study author Elad Ziv, MD, professor of medicine, and colleagues performed genome-wide association analyses of information from the Cancer Prevention Institute of California (CPIC) and the Multiethnic Cohort study. The initial findings in data were replicated from three studies, inevitably incorporating DNA information from 3,140 women with breast cancer, and 8,184 women without the disease.

“The effect is quite significant. If you have one copy of this variant, which is the case for approximately 20 percent (the range being 10 to 25 percent) of U.S. Latinas, you are about 40 percent less likely to have breast cancer. If you have two copies, which occurs in approximately 1 percent of the U.S. Latina population, the reduction in risk is on the order of 80 percent,” said Ziv in a statement.

The findings of the study are published in Nature Communications.