The intended goal of this Project is to develop epigenetic biomarkers to monitor the role of obesity and ethnicity on he development of triple negative breast cancer (TNBC). The proposed approach will seek to clarify for the first time if BMI is a biological factor that regulates aromatic hydrocarbon receptor (AhR) expression and epigenetic activity at breast cancer susceptibility and hormone receptor genes based on Hispanic or non-Hispanic white (NHW) ethnicity. If successful, the proposed experiments have the potential to highlight the role of overweight and obesity for dietary prevention of TNBC and to underscore the consideration of breast cancer screening among overweight/obese Hispanic women. Additionally, this study will provide the opportunity to begin testing the utility of AhR as a biomarker of TNBC development related to BMI and ethnicity.