Breastfeeding boosts immune cells that protect against breast cancer – Nature

Report on the Immunological Benefits of Lactation and its Contribution to Sustainable Development Goal 3

Introduction: Aligning Breast Cancer Prevention with Global Health Targets

A recent study published in Nature provides critical insights into the biological mechanisms by which pregnancy and breastfeeding reduce the risk of breast cancer. The research demonstrates that these physiological processes induce the accumulation of specialized immune cells (CD8+ T cells) that confer long-term protection. This finding directly supports the United Nations’ Sustainable Development Goal 3 (SDG 3): Good Health and Well-being, particularly Target 3.4, which aims to reduce premature mortality from non-communicable diseases, including cancer, through prevention and treatment. The study clarifies how the natural process of lactation contributes to this global health objective.

Research Methodology and Key Stages

The comprehensive study was conducted in three distinct phases to investigate the link between lactation and anti-tumor immunity:

1. Human Tissue Analysis: Researchers examined breast tissue from a diverse cohort of 260 healthy women who had undergone preventive mastectomies or breast reductions. They compared the T-cell counts between women who had given birth and those who had not.
2. Mouse Model Experimentation: To determine a causal link, cancer cells were introduced into mouse models under three conditions: mice that never had pups, mice that experienced forced weaning shortly after birth, and mice that completed a full cycle of lactation and involution. Tumor growth and immune responses were then compared.
3. Clinical Outcome Analysis: The team analyzed data from a population of over 1,000 women diagnosed with triple-negative breast cancer, all of whom had previously given birth. Survival rates and tumor T-cell counts were compared between those who had breastfed and those who had not.

Principal Findings and Implications for SDG 3

The results of the study provide strong evidence for the protective role of breastfeeding and have significant implications for public health strategies aimed at achieving SDG 3.

• Long-Term Immune Memory: Women who had experienced pregnancy and lactation exhibited a higher concentration of long-lived CD8+ T cells in their breast tissue. These protective immune cells were found to persist for up to 50 years, contributing to lifelong health and well-being as envisioned by SDG 3.
• Enhanced Anti-Tumor Immunity: The mouse models demonstrated that a full lactation cycle resulted in smaller tumors and a greater presence of T cells. This confirms that lactation actively enhances both local and systemic immunity, a key mechanism for cancer prevention that aligns with SDG 3.4.
• Improved Survival Rates: In the high-risk group of women with triple-negative breast cancer, a history of breastfeeding was correlated with significantly better survival rates and a higher number of T cells in their tumors. This highlights breastfeeding as a modifiable factor that can reduce mortality from a non-communicable disease.

Conclusion: Strengthening Public Health Policy for Sustainable Development

This research provides a definitive immunological explanation for the known association between breastfeeding and reduced breast cancer risk. By identifying the crucial role of CD8+ T cells activated during lactation and involution, the study reinforces the importance of breastfeeding as a public health imperative. These findings strengthen the evidence base for policies that protect, promote, and support breastfeeding, thereby contributing directly to the achievement of Sustainable Development Goal 3 by reducing premature mortality from cancer and promoting the health and well-being of women and children globally.

Analysis of Sustainable Development Goals (SDGs) in the Article

1. Which SDGs are addressed or connected to the issues highlighted in the article?

• SDG 3: Good Health and Well-being

  The entire article is dedicated to a health-related issue. It discusses a scientific study that explores the biological mechanisms behind how pregnancy and breastfeeding reduce the risk of breast cancer, a major non-communicable disease. The research focuses on improving health outcomes for women by understanding and confirming a key preventive measure. The findings about improved survival rates for women with triple-negative breast cancer who had breastfed directly align with the goal of promoting well-being and ensuring healthy lives.

2. What specific targets under those SDGs can be identified based on the article’s content?

• Target 3.4: By 2030, reduce by one-third premature mortality from non-communicable diseases through prevention and treatment and promote mental health and well-being.

  This target is directly relevant as breast cancer is a non-communicable disease (NCD). The article explicitly addresses both prevention and treatment aspects.

  • Prevention: The study confirms that “Breastfeeding is known to reduce the risk of breast cancer” and identifies the accumulation of “specialized immune cells that reduce the chances of breast cancer developing.” This contributes to the prevention of an NCD.
  • Treatment/Survival: The article states that among women with triple-negative breast cancer, “Those who had breastfed had better survival rates.” This directly relates to reducing premature mortality from NCDs through improved outcomes.

3. Are there any indicators mentioned or implied in the article that can be used to measure progress towards the identified targets?

• Indicators for Target 3.4

  The article mentions or implies several measurable indicators that can be used to track progress towards reducing the impact of breast cancer.

  • Survival Rates: The article explicitly mentions that in a study of over 1,000 women with triple-negative breast cancer, those who “had breastfed had better survival rates.” This is a direct indicator of mortality reduction.
  • Cancer Incidence/Risk Reduction: The central theme is that breastfeeding “reduces the risk of breast cancer.” Measuring the incidence rate of breast cancer in populations with varying breastfeeding rates would be a key indicator of prevention effectiveness.
  • T-cell Count: The study uses the “T-cell count in the removed breast tissue” as a primary biological marker. The finding that women who had children had more long-lived T cells, and that these cells were more numerous in the tumors of women who breastfed, establishes this as a scientific indicator of anti-tumor immunity.
  • Tumor Size: In the mouse model experiments, researchers found that “tumours were smaller in the mice that had lactated.” Tumor size is a common clinical indicator used to measure cancer progression and treatment efficacy.

SDGs, Targets, and Indicators Summary

Source: nature.com