35. DNA methylation age is elevated in breast tissue of healthy women.

Sehl, M. E., et al., 2017

Did you know that various parts of your body may age at different rates? Researchers want to better understand the aging of breast tissue as a way to see at when and where conditions may give way to the rise of breast cancer.

Evidence suggests that female breast tissue ages faster than other parts of the body. Previously, researchers had investigated this phenomenon using unaffected tissue from patients already diagnosed with breast cancer. But we know that such tissue may be exposed to “field effects” of the nearby cancer, such as secretions or other influences.


For this study, researchers used tissue and blood samples from 40 healthy donors from the Komen Tissue Bank to see how an individual’s blood and tissue ages compare. They isolated DNA from the samples to determine DNA methylation age (DNAm). (Methylation is a normal process that can change DNA to protect processes in the body.) Then they took into account the individual’s chronological age.


For the majority of the samples, DNAm age of breast was much older than blood. The degree of separation of the ages was widest among the younger ages. The gap narrowed around the age of menopause, when the age of the blood neared that of the breast. Many reproductive and hormonal factors may influence the faster aging at younger ages of the breast tissue DNAm.

Why this study is important:

At the time of publication, researchers believed this was the first study to demonstrate that breast tissue age exceeds that of blood tissue in healthy female donors. They suggested further studies to investigate other factors that may affect breast tissue age, such as breast density, body mass index, age of first birth and others.