The long-term objective of our research program is to develop breast cancer preventive and therapeutic strategies targeted to specific windows of breast development. The mammary gland is unique in that it goes through several distinct developmental states, such as pubertal or lactational. Our research shows that these distinct windows of mammary gland development are hot spots of risk for breast cancer development and progression. Specifically, our lab identified developmentally regulated stromal-epithelial remodeling programs as the underlying mechanism driving cancer progression during these windows of breast development. While the inherent plasticity of the normal breast microenvironment contributes significantly to breast cancer risk and outcomes, it also provides unique opportunities for life-cycle specific prevention and treatment strategies. By interrogating these windows of development and the impact they have on breast cancer, we hope to develop clinical prevention and control strategies that will reduce breast cancer incidence and improve survival.