5 Exploring the Carcinogenic Potential of Nanoplastics

Abstract Nanoplastics are all around us. Therefore, humans are unavoidably and continuously exposed to them. Among other effects, the accumulation of nanoplastics in tissues and organs has been reported. Due to their persistence, nanoplastics can trigger effects that have been related to the carcinogenic process. Knowing that carcinogenesis is a long-term process, the ubiquity and persistence of nanoplastics, along with the continuous exposure, make them potential carcinogens. Traditionally, short-term genotoxicity tests were performed to assess the carcinogenic potential of agents owing to the well-known capacity of DNA damage and mutation as initiators. However, carcinogenesis is a multi-stage process that involves initiation, promotion, and progression events. The validated Bhas-42 cell transformation assay allows the in vitro simulation of the in vivo initiation and promotion stages of carcinogenesis, thus, the detection of agents with initiating and/or promoting activity. Using the novel Bhas-42 in vitro approach, the carcinogenic potential of polystyrene (PS), polyethylene terephthalate (PET), and polylactic acid (PLA) nanoplastics has been assessed. These plastic types are among the most represented in our daily life as food packages, building insulation, plastic films, electrical and electronic equipment, inner liner for fridges, eyeglasses frames, cleaners, etc. Preliminary results indicate the lack of PS’ carcinogenic potential, which agrees with the reported literature. However, an evident dearth of knowledge about other types of MNPLs, such as PET and PLA, exists. Ongoing research will shed light on the carcinogenic risk of these non-studied nanoplastics to date that could pose a risk to human health.