Brittny C. Davis Lynn, Ph.D., M.P.H.

Dr. Brittny Davis Lynn

Research Fellow / Indipendent Research Scholar
National Cancer Institute
Project Title: “The breast milk microbiome and its relationship with breast cancer risk factors among black and white women.”

Breast cancer is the most common type of cancer among women in the U.S., and it is the second leading cause of cancer-specific death. Breast tumors are categorized into subtypes based on presence or absence of the Estrogen Receptor (ER), Progesterone Receptor (PR) and Human Epidermal Growth Factor Receptor 2 (HER2). Molecular breast tumor subtype is known to vary by age, race and ethnicity, the reasons for which are not well understood, but could include differences in genetic, reproductive, and even lifestyle exposures, such as obesity, age at first birth, and breastfeeding history and duration. For example, research has found that breastfeeding may be associated with decreased risk of ER negative or triple negative (absence of all three receptors) breast cancers.

Human breast milk is a non-invasive biospecimen and may be a valuable risk assessment tool to further our understanding of early events in breast carcinogenesis. Dr. Davis Lynn’s previous work has also identified differences in breast milk DNA methylation and breast milk cytokine levels by race among black and white women. Little is known about the breast tissue microbiota, but researchers have observed differences in breast tissue microbiota between healthy and cancer-afflicted women, and differences in tumor microbiota among women with different molecular categories of breast cancer. Limited data have suggested that the microbiota present in breast milk is measurable, unique and diverse. In collaboration with Dr. Kathleen Arcaro (Breastmilk Laboratory, University of Massachusetts, Amherst), Dr. Davis Lynn’s research team has established the feasibility of measuring breast milk microbiome at NCI’s Center for Genomic Research (CGR).

The proposed project aims at extending upon previous breast milk and microbiome research to a larger population of black and white women, in order to comprehensively evaluate the associations between breast cancer risk factors and the breast milk microbiome. Additionally, risk factor and breast milk microbiome data will be integrated with other breast milk biomarkers, such as DNA methylation and cytokine levels, to examine their inter-relationships, and determine whether racial differences exist in these associations.