Researchers in this study wanted to better understand how normal aging changes in breast tissue influence breast cancer risk. They focused on a process called terminal duct lobular unit (TDLU) involution, which occurs when the milk-producing structures of the breast gradually shrink and decrease in number as women age.
Scientists have long suspected that women with more complete TDLU involution may have a lower risk of breast cancer because there are fewer cells available to undergo cancerous changes. To explore this idea, the researchers reviewed evidence from studies examining TDLU involution and its relationship to known breast cancer risk factors.
The researchers found that the degree of TDLU involution is associated with several factors linked to breast cancer risk, including age, reproductive history, and breast tissue composition. Women with less involution, meaning they retained more glandular breast structures, tended to have a higher risk of developing breast cancer. In contrast, women with more complete involution generally had a lower risk.
The findings suggest that TDLU involution is an important marker of breast tissue aging and may reflect the overall health of the breast. Understanding these structural changes could help explain why some women are at greater risk for breast cancer than others.
