A recent case controlled study by Song Yoa, PhD, and colleagues investigates why African American women tend to have a more aggressive form of breast cancer than those of European Ancestry.
Yao and Colleagues of Roswell Park Cancer Institute in Buffalo show that two variations of a gene, which play specific roles in the metabolism of vitamin D, are associated with an increased risk of estrogen receptor (ER) negative breast cancer in African American women.
However, these gene variations do not increase risk of developing breast cancer in women of European ancestry.
ER-negative breast cancers are known to be more aggressive than ER-positive breast cancer because they are “hormone resistant” meaning they generally are not responsive to hormonal treatment. African American women have a significantly higher risk of developing this aggressive form of breast cancer.
The researchers measured 25(OH)D levels for 1,771 women, as well as associations between risk and variation of 3 genes: one for the vitamin D receptor, and two others involved in vitamin D metabolism.
About 34% of the African American women had severe vitamin D deficiency, while only 6% of the European American women were deficient.
The authors found multiple specific genetic variations of the genes studied among the African American participants. The authors state:
“These data suggest that genetic variants in the vitamin D pathway may be related to the higher prevalence of ER-negative breast cancer in AA women.”
Song Y, et al.Variants in the vitamin D pathway, serum levels of vitamin D, and estrogen receptor negative breast cancer among African-American women: a case-control study. Breast Cancer Research. 2012.