Many Latina Women Protected From Breast Cancer by Genetic Trait

Many women of Latin American descent are less likely to get breast cancer, thanks to a genetic trait many possess, according to studies done by studies on cancer’s ethnic biology.

The findings could lead to more effective genetic testing for women at risk by determining who most needs to take preventative measures. Among women, breast cancer is the most common cancer.

Fewer Hispanic women develop breast cancer, compared with women of European or African-American ancestry, studies show. Researchers may be closer to figuring out why.

Some Latinas have a single difference in just one of the three billion letters of biochemical DNA code in their human genome. This difference makes the Latinas whose genes show it 40% less likely to develop breast cancer, according to a report released yesterday by medical geneticist Laura Fejerman and her colleagues in Nature Communications.

Women are 80% less likely to get breast cancer if they have inherited the variation from both sides of their family.

Studies were funded by the National Cancer Institute, and doctors say further research is necessary to confirm the details of the trend.

High-density breast tissue is a known risk factor for breast cancer. Women who carry the genetic variant have breast tissue that appears less dense on mammograms.

Located on Chromosome 6 near an estrogen receptor gene, the genetic trait is reported to have originated in indigenous American peoples in South America. Not all Hispanic women have the trait. Whether or not a woman has the trait has a lot to do with how much indigenous American ancestry she has.

As many as 20% of Latinas in California are likely to have at least one copy of the variant, which greatly lowers their risk of breast cancer. Puerto Rican women are also less likely to get breast cancer, as a result of the same genetic trait. About 10% of Puerto Rican women are likely to have inherited the trait, the study in Nature says.