Study Links PFAS Exposure in Firefighters to Gene Activity Changes

In a groundbreaking study published on July 25, 2025, researchers from the University of Arizona Mel and Enid Zuckerman College of Public Health have revealed that exposure to per- and polyfluoroalkyl substances (PFAS) may significantly alter gene activity in firefighters, potentially increasing their risk of developing cancer and other diseases. The findings, reported in the journal Environmental Research, mark one of the first investigations connecting PFAS exposure to changes in microRNAs (miRNAs), which are crucial regulators of gene expression.

PFAS are a group of synthetic chemicals widely used in various products, including firefighting foam, non-stick cookware, and cleaning agents, due to their water- and grease-resistant properties. Firefighters are particularly susceptible to these chemicals due to their occupational exposure, raising concerns about their long-term health implications.

According to Dr. Melissa Furlong, an assistant professor of environmental health sciences at the University of Arizona and the study's lead author, "Firefighters tend to have higher PFAS levels due to their occupational exposures. We aimed to investigate the imprint of PFAS exposure on miRNAs and evaluate their association with disease pathways."

The research team analyzed blood samples from 303 firefighters across six states in the U.S. to examine the correlation between PFAS levels and miRNA activity. Specifically, they focused on nine different PFAS compounds and their relationship to various disease pathways. The results indicated significant associations between elevated PFAS levels and alterations in miRNA activity linked to cancers, neurological disorders, and autoimmune diseases.

One of the notable findings involved PFOS (perfluorooctane sulfonic acid), a common PFAS compound, which was associated with reduced levels of miR-128-1-5p, a miRNA implicated in cancer development. Additionally, branched forms of PFOS correlated with changes in five other miRNAs, some of which are known to regulate cancer processes.

Dr. Jeff Burgess, a senior author of the study and a professor at the Zuckerman College of Public Health, has been actively researching firefighter health since 1992. He noted, "Firefighters have requested research on how their exposures lead to increased cancer risk. Identifying epigenetic markers provides a measure of cancer risk and can also be used to evaluate the effectiveness of interventions aimed at reducing this risk."

While the study did not establish direct disease outcomes, it provided critical insights into biological changes that may precede the onset of diseases. Dr. Furlong emphasized the potential of identifying early miRNA signatures as indicators of heightened health risks, saying, "It could be an early indicator of a biological response that could lead to that health outcome."

The implications of these findings are profound, as they underscore the necessity for ongoing research into the effects of PFAS exposure in firefighters and the broader implications for occupational health. The study's results may inform future prevention strategies and interventions aimed at mitigating health risks associated with PFAS exposure in first responders.

As a follow-up, the research team plans to conduct long-term studies to further explore the mechanisms through which PFAS influences disease development among firefighters. "If epigenetics is the mechanism by which PFAS initially works and subsequently results in a range of diseases, then the miRNA could be a modifiable step," Dr. Furlong concluded. "Pharmaceutical companies are already working on treatments that focus on epigenetic modifications, and we have much more work ahead of us."

The research advances our understanding of the intersection between occupational exposure to hazardous substances and long-term health outcomes, highlighting the urgent need for improved safety measures and health monitoring for firefighters.

**Reference:** Furlong MA, Liu T, Jung A, et al. Per- and polyfluoroalkyl substances (PFAS) and microRNA: An epigenome-wide association study in firefighters. Environmental Research. 2025;279:121766. doi:10.1016/j.envres.2025.121766.