Microplastics and nanoplastics in brain tumours and the healthy human brain

Microplastics and nanoplastics (MNPs) are emerging global contaminants of concern, owing to their ability to penetrate human tissues, although their health risks are unknown. MNPs have been detected in several organs, including the brain, but their concentrations in, and effects on, this organ remain largely unexplored. To address this knowledge gap, we analysed 156 diseased brain samples from 113 patients with brain tumours, alongside 35 healthy brain samples from five post-mortem donors. MNPs were present in 99.4% of diseased brain samples and 100% of healthy brain samples. Significant differences in MNP concentration and diameter across tissues suggest distinct pathways for MNP accumulation. A higher MNP concentration was observed in peritumoural brain tissues than in healthy brain tissues, suggesting that the compromised blood–brain barrier in cancer may aid MNP entry. A positive correlation between microplastic surface area and tumour proliferation was observed. This study provides evidence of MNP presence in the living human brain, highlighting a need for further research to understand causal links between MNPs and human disease. Microplastics and nanoplastics were found at a higher level in brain tumour samples from living patients than in healthy human brain samples from cadavers, with a correlation between microplastic surface area and tumour proliferation.