Article title: Associations between paraben exposure and breast cancer risk: An integrative epidemiologic, network toxicology, multi-omics and experimental analysis

Breast cancer is the most common malignancy among women worldwide, with environmental chemical exposure increasingly implicated in its development. Parabens (PBs) are widely used preservatives with endocrine-disrupting properties, but their role in breast carcinogenesis remains unclear. This study integrated epidemiological analyses of the National Health and Nutrition Examination Survey (NHANES), network toxicology, machine learning, transcriptomic profiling, molecular docking, and in vitro assays to investigate associations between PBs exposure and breast cancer risk and to explore potential mechanisms. NHANES analysis (2005-2016, n = 9615) revealed significant associations between higher urinary concentrations of ethyl paraben (EPB), methyl paraben (MPB), and propyl paraben (PPB) and breast cancer prevalence. Network toxicology identified 14 candidate molecular targets, with estrogen receptor 1 (ESR1), enhancer of zeste 2 polycomb repressive complex 2 subunit (EZH2), and platelet-derived growth factor receptor alpha (PDGFRA) prioritized through machine learning and SHapley Additive exPlanations (SHAP), highlighting EZH2 as the most influential predictor. Transcriptomic analyses indicated these hub targets influence immune cell infiltration and exhibit distinct expression patterns within the tumor microenvironment. Molecular docking simulations suggested strong interactions between PBs and these hub proteins. In vitro assays demonstrated that PBs upregulated ESR1 and EZH2, induced DNA damage in normal breast epithelial cells, and enhanced proliferation and migration in breast cancer cells-effects reversed by ESR1 and EZH2 inhibitors. Together, these findings suggest that PBs may affect pathways relevant to breast cancer progression and act as potential environmental contributors.