An analysis of more than 55,000 women has revealed that breast density, microcalcifications, and masses may be heritable, according to a study in Cancer Research report on by the American Association of Cancer Research.

“Breast features identified through mammography are important for identifying women at high risk of developing breast cancer in the short term,” said Natalie Holowko, PhD, postdoctoral researcher in the department of Medical Epidemiology and Biostatistics at the Karolinska Institutet in Stockholm. “It is important to understand the genetic determinants of these traits, as the underlying mechanisms for their association with breast cancer is not well understood.”

The researchers calculated the heritability of four mammographic features – breast density, average density change per year (cm2/year), microcalcifications, and masses – using 1,940 sister pairs. The heritability of breast density was estimated to be 58 percent, similar to previously reported findings. The heritability of microcalcifications and masses were estimated to be 23 percent and 13 percent, respectively. Breast density change was not determined to be an inherited trait.

Holowko and colleagues investigated the associations between mammographic features and genetic predisposition to breast cancer, as determined by a polygenic risk score (PRS), among 9,365 women in the KARMA cohort. They found statistically significant positive associations between PRS quintiles and breast density and microcalcifications.

Read more from AACR and find the study in Cancer Research