New research shows that women living near superfund sites are more likely to develop aggressive and metastatic breast cancer. The study found a higher risk of hard-to-treat subtypes such as triple-negative breast cancer, especially in areas with more air pollution. The researchers discovered molecular changes in the tumors related to ambient pollution. The findings point to environmental exposure as a key factor influencing breast cancer outcomes. Place of residence may thus contribute to more aggressive forms of the disease. Social conditions also shape cancer progression and outcomes.