In a case-control
study, Song Yao, PhD of Rosewell Park Cancer Institute in Buffalo said that two
variants in a gene playing an important role in the metabolism of vitamin D
was associated with an increased threat of estrogen-receptor (ER) negative
in African American women.
Researchers state that
same gene variant showed no effects in women of European ancestry.
American women are
expected to have more ER-negative breast cancer risk than European
counterparts.. They are also likely to have reduced levels of circulating
25-hydroxyvitamin D. 25-hydroxyvitamin D is a major marker and a metabolite of
vitamin D. It is concerned with ER-negative tumors in European women.
Yao et al believed
that the racial differences in genetic variation in the pathway of vitamin D
and 25-hydroxyvitamin D (25 OHD) might result in observed differences in the
characteristics of tumor.
A case-control study was conducted and about 1,771 females
were enrolled for the study.
The serum 25OHD levels
were measured and tested; relation between variation and risk in three genes
was studied: two for vitamin D metabolism (CYP24A1 and CYP27B1) and one
for vitamin receptor.
In the study, 928 females had breast cancer. 547 women
were African Americans and 381 were from European ancestry.
Since breast cancer
treatment affects levels of vitamin D, the researchers analyzed this
crucial aspect in the control group. The African Americans had serum 25OHD
levels of 14.0 ng/mL as compared to 21.4 in European women.
The study analysis
revealed that 34.3% of African Americans had severe deficiency of vitamin D
with low serum 25OHD levels of 10ng/mL while merely 5.9% of European women had
severe vitamin D deficiency.
The experts found a single nucleotide polymorphisms-single
base pair alterations-differed by race and ethnicity.
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; Song Yao et al; Breast Cancer Research