What the body needs to resist breast cancer may have been inside it all along. That is, if you're a Latina woman.
An international study led by researchers from UC San Francisco has discovered a gene variant that protects Latina women from breast cancer. Called the single-nucleotide polymorphism (SNP), it represents a difference in one of three billion components in the genome, providing Latina women with significant protection against breast cancer, most especially its particularly aggressive forms that are estrogen receptor-negative.
Published in Nature Communications, the study highlighted that women carrying SNP have breast tissues that appear to be less dense in mammograms. High mammographic density is considered as a risk factor for breast cancer.
According to Elad Ziv, MD, senior author for the study, in one copy of the variant SNP, which is likely in about 20 percent of Latinas in the United States, there is a 40 percent reduction in breast cancer risk. If two copies of the variant is present, which is reported in around 1 percent of Latina women in the U.S., risks are further reduced by a whopping 80 percent.
Historically, Latina women have been shown to be less prone to breast cancer and this is what Ziv and Laura Fejerman, PhD., first author for the study and a part of the Institute of Human Genetics at the UCSF, sought to explain, studying Latina populations for many years looking for biological and genetic reasons.
For this study, Ziv, Fejerman, and colleagues did genome-wide analyses that sought out associations in datasets provided by the Cancer Prevention Institute of California, as well as a study called the Multiethnic Cohort. DNA samples and other data from self-identified Latinas or Hispanics were used for this study, totaling 722 controls and 977 cases of breast cancer.
SNP was discovered on Chromosome 6, close to a gene code utilized by ESR1, a receptor for estrogen. Further research is needed but preliminary experiments show that SNP works by interfering with how transcription factors work. Transcription factors are proteins that normalize ESR1 expression.
"If we can use these results to better understand how this protects estrogen receptor-negative breast cancer, that would be interesting and important because right now we have no good way to prevent that type of breast cancer," said Ziv.
Funded by the National Cancer Institute, the study involved collaboration with Laura J. Van ‘t Veer, PhD and Laura J. Esserman, MD, MBA, both professors of medicine at USCF.