Study Examines Immune Cells as Predictors of Breast Cancer Risk

Overview of Leukocytes

A recent study has explored the relationship between specific immune cells, known as leukocytes, and breast cancer risk. Leukocytes, or white blood cells, play a crucial role in defending the body against infections and are produced in the bone marrow. This group includes various subtypes, such as monocytes and B cells. Monocytes are the largest leukocytes and can differentiate into other types of cells, while B cells, also referred to as B lymphocytes, are responsible for producing antibodies.

Key Findings from the Study

Published in the Journal of the American Medical Association, the study indicates that certain leukocyte subtypes may be linked to breast cancer risk, potentially months to years after blood samples are collected. The research was based on a small cohort drawn from the Sister Study, a larger investigation that enrolled over fifty thousand women.

Leukocyte Subtypes Analyzed

Researchers evaluated six subtypes of leukocytes and their correlation with breast cancer risk:
– B cells
– Natural killer cells
– CD8 T cells
– CD4 T cells
– Monocytes
– Granulocytes

Blood samples were taken from participants, and complete blood cell count data was analyzed. The study assessed the methylation-derived neutrophil-to-lymphocyte ratio, along with the proportions of the leukocyte subtypes. Additionally, the stability of these subtypes over time was examined, revealing that they generally remain stable.

Increased Levels of B Cells Linked to Risk

The study found that higher circulating levels of B cells were associated with an increased risk of breast cancer, particularly among premenopausal women. Those who developed breast cancer tended to be older and less physically active. While age correlated with levels of natural killer cells, it did not show the same relationship with B cells. Women exhibiting proportions of natural killer cells, CD8, and CD4 T cells above the subcohort median faced a heightened risk of breast cancer. Additionally, elevated levels of granulocytes or CD8 T cells were associated with an increased risk of breast cancer four years after blood collection.

The Role of Circulating Immune Cells as Biomarkers

This study enhances the understanding of the immune system’s potential involvement in breast cancer risk. Future monitoring of breast cancer risk may leverage women’s immune system profiles. According to the authors, Kresovich et al., changes in circulating leukocyte profiles could occur prior to clinical diagnoses of breast cancer and may serve as time-dependent markers, especially in premenopausal women. It is essential to note that the study was primarily observational and could only evaluate leukocyte proportions at the initial follow-up, without assessing the implications of any changes in leukocyte levels.

References

Kresovich JK, O’Brien KM, Xu Z, Weinberg CR, Sandler DP, Taylor JA. Prediagnostic immune cell profiles and breast cancer. JAMA Netw Open. 2020;3(1):e1919536. doi:10.1001/jamanetworkopen.2019.19536.