'Very concerning': Microplastics can accumulate in cancer cells and may help them spread, study hints

Microplastics may hang around in the body longer than scientists previously thought and may contribute to the spread of cancer when inside tumors, a lab-dish study suggests.

The research has several limitations, however. For instance, the scientists used cancer cells grown in lab dishes, so it remains to be seen how the results apply to real-life biological systems beyond controlled lab conditions. The microplastics studied also differ somewhat from those found in the environment, because the latter have different shapes and degrade in specific ways.

Nonetheless, the lab-dish study's findings are "very concerning," Nicholas Chartres, a researcher who studies microplastics at the University of California, San Francisco and the University of Sydney, told Live Science in an email. "These types of studies are critical early warning signs for us to act," said Chartres, who was not involved in the new research.

Micro- and nanoplastics (MNPs) most commonly enter the body through inhalation or, slightly less commonly, through ingestion. Previous research has shown that smaller MNPs — which have diameters less than 10 micrometers and are found in single-use water bottles — are more invasive than larger particles. Studies in lab-grown cells and mice have shown that such particles can penetrate cell membranes, accumulate in cells and trigger cellular stress.

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However, how MNPs build up in cells is poorly understood.

Now, a study published in February in the journal Chemosphere has shown that MNPs can get passed from one cell to its next generation when the cell divides in two. What's more, the plastics show no signs of being eliminated from the cells.