Scientists crack air pollution cancer link with ‘era defining breakthrough’

A research team at the Francis Crick Institute in London found evidence that cells absorb damage as we grow and age, but for these cells to become cancerous, a gene must be triggered by something. This is contrary to current understanding, where it was believed that cancer starts with a healthy cell and as the genetic code becomes increasingly mutated, the cell becomes cancerous and begins to divide and grow uncontrollably, spreading to surrounding tissue .

In the new findings, which have been presented at a conference of the European Society for Medical Oncology (ESMO) this week, the researchers focused on particulate matter (PM2.5).

PM2.5 is typically found in exhaust gases and fossil fuel smoke and is associated with the risk of non-small cell lung cancer (NSCLC), which accounts for thousands of deaths globally each year, according to Turner et al in CA: A Cancer Journal for Clinicians.

Through a series of human and animal studies, the researchers found that PM2.5 causes inflammation in the lungs when inhaled and leads to the release of interleukin-1-beta in the lungs, a chemical alarm that activates cells to help repair damage. Currently, laboratory interleukins are sometimes used to boost the immune system in cancer treatment.

They found that about one in every 600,000 cells in the lungs of a 50-year-old already contains potentially cancerous mutations, but these are healthy until activated by the chemical alarm when they become cancerous.

By blocking this alarm, the researchers were able to stop cancer formation in mice exposed to air pollution. The researchers said these findings transform the understanding of both how people get cancer and the impact of air pollution on cells.

Francis Crick Institute and Cancer Research UK Chief Clinician Professor Charles Swanton summarized the findings at ESMO: “The same particulate matter in the air that originates from the burning of fossil fuels is exacerbating climate change, directly affecting human health via an important and previously overlooked cancer-causing mechanism in lung cells.

“The risk of lung cancer from air pollution is lower than from smoking, but we have no control over what we all inhale. Globally, more people are exposed to unsafe levels of air pollution than to toxic chemicals in cigarette smoke, and this new data links the importance of addressing climate health to improving human health.”

Swanton told the BBC the breakthrough was the “most exciting discovery his lab had come across” and said it marked a “new era in the fight against cancer”.