Abstract 4298: Cytokines and adipokines in breastmilk of black and white women
Authors: Murphy Jeanne , Sherman Mark E. , Pfeiffer Ruth M. , Yang Hannah P. , Caballero Ana I. , Browne Eva P. , Gierach Gretchen L. , Arcaro Kathleen F. 
Published: July 2016

Introduction: Giving birth may be associated with a transient increase in breast cancer risk post-delivery and with elevated risk of basal breast cancers, especially in the absence of breastfeeding, whereas parity is related to lower risk of postmenopausal ER-positive tumors. Black women develop more early-onset and basal breast cancers than White women, but factors contributing to this disparity are poorly understood. Accordingly, we compared levels of 15 proteins with hypothesized roles in breast cancer risk in breastmilk from healthy Black and White women.

Methods: We tested breastmilk donated by 130 Black and 162 White women, annotated with breast cancer risk factor questionnaire data. Following pilot testing using the MesoScale Discovery system (Rockville, MD), the following analytes were measured in breastmilk, adjusted for total protein concentration: interferon-γ, IL1-β, IL-6, IL-8, TNF-α, FLT-1, TIE-2, PlGF, VEGFC, VEGFD, adiponectin, leptin, and FAS-L. M30-apoptosis and Bradford protein were measured with Molecular Devices VersaMax reader (Sunnyvale, CA). Univariate associations of race with women's characteristics were computed using chi square tests and t-tests. Multivariable logistic regression models with a random effect to account for plate effects were used to assess the associations (odds ratios (ORs) and 95% confidence intervals (CIs)) of analyte levels with: race, family history of breast cancer, smoking, baby's age in days, body mass index at time of sample donation, age, menarche, age at first birth, return of menses, parity, and over-the-counter pain medication.

Results: Of the 15 analytes measured, all but VEGFC and TIE2 were detectable and reliably measured. Black women compared to White women had higher BMI (p = 0.05) and higher parity (p = 0.02), and were younger age at menarche (p = 0.005) and younger age at first birth (p = 0.01). White women had higher levels of smoking (p = 0.01) and more frequently had a first degree relative with breast cancer (p = 0.03). Compared with White women, Black women had significantly higher levels of IL1-β (OR 1.77, 95% CI 1.13 - 2.77, p = 0.01) adjusting for the baby's age in days. Black women had significantly higher levels of leptin (OR 2.01, 95% CI 1.28 - 3.15, p = 0.002) and leptin/adiponectin ratio (OR 2.36, 95% CI 1.49 - 3.72, p = 0.0004), even after adjusting for body mass index.

Discussion: Preliminary data demonstrate differences in levels of putative markers of breast cancer risk between White and Black women, including IL1-β, leptin and the leptin/adiponectin ratio. These data suggest that further analyses of biomarkers in breastmilk may be useful for understanding breast cancer risk and to identify possible factors that may be associated with racial disparities in early onset and basal breast cancers.

Citation Format: Jeanne Murphy, Mark E. Sherman, Ruth M. Pfeiffer, Hannah P. Yang, Ana I. Caballero, Eva P. Browne, Gretchen L. Gierach, Kathleen F. Arcaro. Cytokines and adipokines in breastmilk of black and white women. [abstract]. In: Proceedings of the 107th Annual Meeting of the American Association for Cancer Research; 2016 Apr 16-20; New Orleans, LA. Philadelphia (PA): AACR; Cancer Res 2016;76(14 Suppl):Abstract nr 4298.