Australian researchers have uncovered a groundbreaking link between breastfeeding and long-term breast cancer prevention, revealing how the body's immune system becomes a lifelong guardian against the disease. A study led by the Peter MacCallum Cancer Center shows breastfeeding triggers specialized immune cells to permanently reside in breast tissue, acting as vigilant protectors against cancerous growths.
Published in Nature, the research identifies CD8⁺ T cells that accumulate during pregnancy and lactation cycles. These cells remain active for decades, functioning as biological security teams that detect and destroy abnormal cells. Professor Sherene Loi, lead author, explains: "These cellular guardians evolve to protect mothers during vulnerable post-pregnancy periods, but their cancer-fighting benefits persist long-term."
The study analyzed over 1,000 patient cases and conducted preclinical trials, finding that women who breastfed developed tumors with 30% more protective T cells compared to non-breastfeeding counterparts. Triple-negative breast cancer – the most aggressive subtype – showed particularly strong responsiveness to this immune defense mechanism.
While hormonal changes were previously thought responsible for breastfeeding's protective effects, this research shifts focus to localized immune system remodeling. The discovery opens new avenues for preventive therapies that could mimic these natural processes, potentially benefiting women unable to breastfeed.
With Australia recording 58 new breast cancer diagnoses daily – and rising rates among younger women – these findings carry significant public health implications. Researchers emphasize that while breastfeeding duration impacts protection levels, even short-term nursing provides measurable benefits.
