Tracing the malignant trajectory of microplastics and nanoplastics: Biological pathways potentially implicated in carcinogenesis (Review)

Microplastics and nanoplastics have emerged as significant environmental challenges, exerting a considerable impact on ecosystems.Simultaneously, a growing body of evidence indicates their accumulation within human tissues and organs, including tumor samples from patients with cancer, thereby raising concerns about their potential implications for human health.In recent years, extensive research has demonstrated that exposure to plastic particles induces toxicity, with the overproduction of reactive oxygen species (ROS) being one of the most prominent effects.ROS subsequently trigger oxidative stress, DNA damage, genotoxicity and chronic inflammation, while dysbiosis and endocrine disruption have also been associated with plastic exposure, among other effects.Apart from observations from in vitro and in vivo experiments suggesting that exposure to plastics can modulate critical signaling pathways, a number of which are linked to carcinogenesis, a critical question arises regarding the potential role of exposure to plastics in the development of cancer.To address this issue, the present review aimed to integrate mechanistic evidence concerning the potential implications of plastics in carcinogenesis.Particular attention was paid to biological pathways that may contribute to tumor initiation and progression, rather than seeking to establish a definitive causal association.