Pregnancy and Breastfeeding - New Research Shows Value in Reducing Cancer Risks : Shared by Tom McDermott

Oncologist Sherene Loi

Breastfeeding Has Long Been Linked to Reducing Cancer Risk. Scientists May Have Just Discovered Why
Marta Hill — Smithsonian Magazine, 24 October 2025
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Summary
Recent research found that women who breastfed had higher levels of specialized CD8+ T immune cells in their breast tissue—cells that can persist for decades and may help protect against aggressive breast cancers. In lab mice, those that went through full pregnancy, lactation and mammary recovery developed more of these cells and showed slower tumor growth when challenged with cancer cells. While the findings focus on triple-negative breast cancer and don’t yet explain all types, they lay the groundwork for new immune-based prevention strategies.

See also
CD8+ T Cells: Foot Soldiers of the Immune System

Quotes

“These cells act like local guards, ready to attack abnormal cells that might turn into cancer.”
“Having babies and breastfeeding causes long-lasting changes in immune cells that could help protect the breast from cancer.”
“What this study enables us to do is get a better understanding of the immune cell types … that might be more important to target with emerging therapies.”