Researchers in this study wanted to understand how the breast changes after breastfeeding ends (weaning) and how these changes might affect breast cancer risk. While pregnancy is known to have both protective and short-term risk effects, scientists have been particularly interested in the period after childbirth when the breast returns to its normal state.
To investigate this, the researchers studied the process called breast involution, which is when the breast tissue shrinks and remodels after lactation stops. They analyzed breast tissue samples from women at different stages after weaning to observe structural and biological changes.
They found that during this period, the breast undergoes rapid tissue breakdown and rebuilding, similar to a wound-healing process. This includes the loss of milk-producing cells, increased activity of immune cells, and changes in the surrounding tissue structure. These changes create a temporary inflammatory environment, which may support tumor growth if cancer cells are present.
Overall, the study suggests that the period after weaning may represent a window of increased breast cancer risk, due to changes in the tissue environment that can promote cancer progression.
