Microplastics and Cancer: A Comprehensive Review of Their Impact on Tumor Progression and Mechanisms of Carcinogenesis

Microplastics (MPs), pervasive environmental pollutants, have raised significant concerns regarding their potential impact on human health, particularly in relation to cancer. This review examines the current evidence linking MPs to various cancers, including ovarian, gastric, blood, brain, colorectal, lung, liver, breast, and cervical cancers. Recent studies indicate that MPs, including polystyrene nanoparticles (PS-NPs) and microplastics (PS-MPs), can exacerbate tumor progression through mechanisms such as oxidative stress, inflammation, and endocrine disruption. For instance, in ovarian cancer, PS-NP exposure has been shown to accelerate tumor growth, while in gastric cancer, PS-MPs alter gene expression to promote cancer progression. Blood cancer research highlights the presence of MPs in human blood, suggesting their potential systemic distribution and impact. MPs' ability to cross the blood-brain barrier raises concerns about brain cancer, where they may induce neurotoxicity. Similarly, MPs contribute to colorectal cancer by causing intestinal inflammation and gut microbiota alterations. Inhalation of MPs is linked to lung cancer due to chronic inflammation and oxidative stress. In liver cancer, MPs induce hepatic toxicity and promote carcinogenesis. Breast and cervical cancers are associated with MPs endocrine-disrupting properties, leading to increased cell proliferation and migration. This review underscores the urgent need for further research to elucidate the mechanisms through which MPs contribute to cancer and to inform public health strategies and regulatory policies aimed at mitigating the risks of microplastic exposure.