Determination Of Normative Patterns Of Gene Expression Levels And Breast Cancer Risk Biomarkers In Human Breast Milk

Abstract Parity and breastfeeding influence a woman’s risk of developing breast cancer. Understanding the underlying molecular changes in the breast will facilitate identification of additional factors during pregnancy and postpartum that modify breast cancer risk. Most prior studies in humans on this topic, however, have been cross-sectional studies comparing breast tissue samples from nulliparous versus post-pregnant women, and are limited in their ability to characterize longitudinal changes and within-person variations. Breast milk contains cells of the mature gland, and may have a potential as a noninvasive source for studying molecular characteristics of the pregnancy-associated changes in the breast and their impact on breast cancer risk. The objectives of this study were to (1) determine normative patterns of gene expression levels in longitudinally collected breast milk samples and (2) correlate gene expression data in relation to self-reported measures of psychosocial stress during pregnancy and postpartum period. Our preliminary results showed that the post-pregnancy gene expression levels in breast milk samples can be measured reproducibly over a short period of time. Whole-genome transcriptome analysis revealed that expression levels of the post-pregnancy genes are different in early (less than 3 month postpartum) and late lactation period (more than 6 month postpartum). Moreover cytokine expression profiling correlated expression of inflammatory cytokines with early versus late postpartum period. The unique contribution of this study is to capture longitudinal gene expression data from breast milk samples collected over the course of lactation, hence providing a valuable basis for future studies to identify differential dynamics associated with breast cancer susceptibility. Note: This abstract was not presented at the meeting. Citation Format: Maria Ouzounova, Georgina Lewis, Raziye Piranlioglu, Tiana Curry-McCoy, Wonsuk Yoo, Nita Maihle, Sangmi Kim, Hasan Korkaya. Determination of normative patterns of gene expression levels and breast cancer risk biomarkers in human breast milk [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2017; 2017 Apr 1-5; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2017;77(13 Suppl):Abstract nr 4240. doi:10.1158/1538-7445.AM2017-4240