First responders to the 9/11 attacks have an increased number of mutations in their blood that may predispose them to blood cancers and cardiac disease, according to a new study. The results highlight the attacks' long-lasting impact on first responders to the site, who breathed in a cocktail of harmful carcinogens while they attempted to rescue victims and stabilize the scene.
The study is published in Nature Medicine.
As the World Trade Centers (WTC) fell, extreme amounts of dust, toxic gas, and carcinogens were kicked up into the surrounding area, forcing responders to breathe it in if they wished to get close to the rubble. Campaigns for extended health coverage for these individuals have raged ever since the event, with TV host Jon Stewart famously advocating for the funding of healthcare for personnel that attended the scene and condemning Congress for their inaction.
Scientists from Vanderbilt-Ingram Cancer Center (VICC) wished to delve deeper into the exact implications these personnel could now face, over 20 years after the event, and began collaborating with researchers from New York to analyze health differences between 9/11 first responders and firefighters that didn’t attend the attacks.
The study looked at over 700 firefighters, around two-thirds of whom were present at the World Trade Centre collapse and another third who were age and lifestyle-matched, but were not present at 9/11.
Blood samples were taken for each and analyzed closely, uncovering the number of somatic mutations that could be found in the blood cells of each.
The researchers discovered that there was a significantly higher proportion of firefighters from the World Trade Centers that had mutations in their blood cells suggestive of clonal hematopoiesis (CH) – which is where stem cells that eventually turn into blood cells begin creating cells with the same genetic mutations. CH is typically found in people that smoke, as well as people exposed to genotoxic substances.
When the researchers exposed modified human immature white blood cells to particulates from the WTC, they identified the dust was interfering with DNA replication at fragile sites in the genome.
To further identify if this could have a detrimental effect, the researchers exposed mouse models to particulate matter from the WTC, in an equivalent amount to what the first responders likely received. The mice had a significantly increased expansion of hematopoietic stem cells – which can become many different cells in the body – after 30 days, suggesting the particulate matter was affecting the production of blood cells.
The results suggest firefighters that attended the attacks have an increased mutational burden (the number of non-inherited mutations in a genomic sequence), which increases their risk of developing blood cancer.
Such risk means the thousands of injured people that survived 9/11, including many first responders, need increased screening to identify lingering impacts of the attacks and may require additional support as they age.
The team from VICC now hope to illuminate exactly how this particulate matter results in the genetic changes.