Washington: A leading personal genetics company has identified seven single-nucleotide polymorphisms (SNPs) significantly associated with breast size, including three SNPs also correlated with breast cancer in a genome-wide association study (GWAS).
23andMe made these findings, which make the first concrete genetic link between breast size and breast cancer risks, using data from its unique online research platform.
These findings were made analyzing data from 16,175 female 23andMe customers of European ancestry, comparing their answers to survey questions including bra cup size and bra band size to genetic data at millions of SNPs. The analysis controlled for age, genetic ancestry, breast surgeries, breast feeding status and pregnancy history.
“The 23andMe research platform is a robust source of new genetic discoveries and this study demonstrates that important scientific insights can come from the most unlikely places,” stated 23andMe CEO and co-founder Anne Wojcicki.
“Nearly 90 percent of our more than 150,000 customers participate in our online research allowing 23andMe to make discoveries faster and more cost effectively than traditional research models,” added Wojcicki.
While some factors of breast morphology, such as density, are known to be directly implicated in breast cancer, the relationship between breast size and cancer is less clear. While breast size is heritable, this study is the first to identify genetic variants linked to differences in breast size.
“The findings in this study show that some of the same biological pathways underlie both normal breast growth and breast cancer,” explained lead author Nicholas Eriksson, Ph.D.
“Some studies have found that larger breast size as a young woman is associated with a slightly higher risk for breast cancer. The genetic factors we found support this concept that breast size and breast cancer are related,” Eriksson added.
“These results provide insight into the genetic factors underlying normal breast development and show that some of these factors are shared with breast cancer,” concluded Eriksson.
The findings are now available online in BMC Medical Genetics.