Environmental factors influencing hormone receptor positive breast cancer incidence: integrating chemical signatures from dust wipes with self-reported sources of exposure.

BACKGROUND: Breast cancer is a highly prevalent disease. Chemical exposures may contribute to breast cancer risk, though most chemicals to which humans are exposed remain understudied in breast cancer research. OBJECTIVE: This study tested the hypothesis that environmental chemicals present in households of women who do and do not develop breast cancer will have differential abundance, and that chemical profiles relate to self-reported sources of exposures. METHODS: Household dust wipe samples were collected at enrollment in the Sister Study cohort in 2003-2009. We evaluated a subsample of Sister Study participants who developed hormone receptor positive breast cancer within 10 years after enrollment (N = 40, "cases") and who remained breast cancer free during the same period (N = 40, "controls"). Dust wipes were analyzed via liquid chromatography with tandem mass spectrometry coupled with database mining approaches. Participants self-reported personal care product usage and proximity to environmental pollution sources. Frequent itemset mining (FIM) was used to evaluate chemical occurrence and associations with questionnaire data. RESULTS: In the dust wipe samples, there were 189 features annotated to potential chemicals that significantly differed (adjusted p < 0.1) in abundance between cases and controls. Example chemicals included suspected endocrine disruptors 23-(Nonylphenoxy)-3,6,9,12,15,18,21-heptaoxatricosan-1-ol, triethanolamine, and thiabendazole. Analysis of questionnaire data identified the chemical 6-benzyl-2-[bis[(2S)-2-aminopropanoyl]amino]-3-methylphenyl] (2S)-2-[[(2S)-2-(3-hydroxyhexanoylamino)-3-methylbutanoyl]amino]-3-methylbutanoate to be of high interest due to its link, derived through FIM, to 45 exposure scenarios, largely described by elevated personal care product usage habits. SIGNIFICANCE: Overall, this study builds the evidence base for understudied chemicals in everyday household environments that may alter breast cancer risk. Coupling chemical analysis results with participant survey data highlighted behaviors and environmental factors that may influence exposures to these chemicals, informing the design of future investigations to better understand sources of breast cancer risk in women. IMPACT: There is much to understand about household exposures that can affect breast cancer risk. This study aimed to generate a novel household exposomic dataset leveraging dust wipe samples from the Sister Study cohort. A subset of the detected chemicals was found to be differentially detected in the houses of women who developed breast cancer. Additional analysis of self-reported questionnaire data demonstrated linkages between increased personal care product usage and elevated chemical abundance. The results of this study lend important insights into understudied chemicals in the home that may alter breast cancer risk and possible sources of exposure to these substances.