(Vienna, 15 July 2025) Although the respiratory system is one of the main entry points for microplastics and nanoplastics (MNPs) from the air into the body, little is known about the effects of these tiny particles on the lungs. Researchers at MedUni Vienna have now demonstrated for the first time that MNPs can trigger malignant changes in lung cells that are associated with the development of cancer. The findings were published in the Journal of Hazardous Materials and once again underline the urgent need for action to reduce plastic waste.

As part of the study, the research team led by Karin Schelch, Balazs Döme and Büsra Ernhofer (all from the Department of Thoracic Surgery and the Comprehensive Cancer Centre at MedUni Vienna) investigated how polystyrene micro- and nanoplastics (PS-MNPs) interact with different types of lung cells. Polystyrene is a plastic widely used in everyday objects, including food packaging and disposable items such as yoghurt pots and coffee-to-go cups. The surprising result of the research: healthy (non-malignant) lung cells absorb particularly small particles (0.00025 millimetres) of PS-MNPs significantly more than malignant cancer cells – and react with biological changes that once again highlight the health risks posed by MNPs.

Specifically, after contact with the particles, the healthy cells showed increased cell migration, DNA damage, oxidative stress and the activation of signalling pathways that promote cell growth and survival – all processes that are considered early indicators of cancer development. "Particularly striking was the reduced ability of healthy cells to repair DNA damage and the simultaneous activation of certain signalling pathways that normally promote cell growth," said study leader Karin Schelch, providing details.

Long-term effects still unclear
While lung cancer cells remained relatively unaffected under the same conditions, even short-term exposure to MNPs could be enough to influence healthy lung cells in a direction associated with malignant changes. According to the latest research findings, the cells' defence mechanisms were also triggered under the influence of polystyrene particles. "We observed the activation of antioxidant defence systems – an indication that the cells are actively defending themselves against the stress caused by plastic particles," explains first author Büsra Ernhofer.

The lungs are considered one of the main routes of exposure to airborne microplastics. However, little was known about how these particles interact with lung tissue cells. "The data now available provide initial indications that healthy lung cells in particular react in a way that gives cause for concern," says co-study leader Balazs Döme. This opens up new questions about the possible link between plastic pollution, chronic lung disease and cancer development – and underscores both the need for interdisciplinary research at the interface between environmental medicine and cancer biology and the need for action to reduce plastic waste. In addition, the long-term effects of MNP exposure on the lungs remain unclear and, according to the research team, need to be investigated urgently.