Can genes for mammographic density inform cancer aetiology?

Abstract

High mammographic density (MD) is an established risk factor for breast cancer. In theory, the number of genes that regulate MD should be smaller than that influencing breast cancer risk. How informative have the initial studies of the genetics of MD proved to be? Mammographic density (MD) reflects variations in fat, stromal and epithelial tissues that are thought to be regulated by several genes. High MD is an established risk factor for breast cancer; therefore, genes that regulate MD may indirectly influence breast cancer. These genes might also be fewer in number and easier to identify than those for breast cancer risk outside of inherited predisposition syndromes. In this Perspective, we review the limited genetic studies of MD and propose future directions.