A non-targeted approach to identify potential breast carcinogens in women firefighters after a fire event

Abstract

BACKGROUND AND AIM: Female firefighters remain understudied in both exposure and epidemiology studies. Furthermore, occupational studies generally focus on toxic chemicals that are well characterized. The objective of this study was to identify potentially novel chemical exposures associated with a fire event among female firefighters. METHODS: We applied non-targeted analysis methods to three longitudinal serum samples collected in the days and weeks after a fire. To assess exposure to potential breast carcinogens among women workers after an urban structural fire event the Women Workers Biomonitoring Collaborative (WWBC), we recruited female firefighters in San Francisco and developed a biospecimen archive. Female firefighters (n=18) were recruited and provided 3 serum samples—within 48 hours, 1 week, and 1 month after fighting a fire. We applied a non-targeted analytical approach with liquid chromatography quadrupole time of flight mass spectrometry (LC-QTOF/MS) in both the positive and negative ionization modes. RESULTS:We detected over 20,000 features, representing potential chemical exposures in study participants. Exact masses of features were matched to a curated in-house library of 7,935 environmental chemicals and potential breast carcinogens, tentatively identifying 1,667 chemicals. MS/MS fragmentation analysis allowed us to further confirm 181 candidate chemicals based on the predicted fragmentation pattern of each chemical. These chemicals included per-/poly-fluoroalkyl substances, endocrine disrupting chemicals and chemicals associated with mammary tumor development. We will confirm the identity of at least 5 of these novel chemicals by re-running the samples with known standards. CONCLUSIONS:Non-targeted analytical approaches in carefully designed exposure studies can help “look beyond the lamp post” to identify novel exposures with health concerns. KEYWORDS: non-targeted analysis, generalized suspect screen, occupational exposures, internal exposome