There is a growing concern regarding the potential health effects that continuous exposure to environmental micro- and nano-plastics (MNPLs) may cause on humans. Due to their persistent nature, MNPLs may accumulate in different organs and tissues and may induce in the long term the development of cancer. The present study aimed to review the existing literature on the carcinogenic potential of MNPLs. As studies directly assessing carcinogenicity were expected to be scarce, studies dealing with indirect outcomes associated with the carcinogenic process were considered in the literature search. Of the 126 studies screened, 19 satisfied the inclusion criteria. Besides, 7 additional cross-referenced articles, identified through a careful reading of the previously selected papers, also met the inclusion criteria and, consequently, were included in the review. Most of the selected studies were performed using in vitro models whereas about 40% of the studies were done in rodents, although none of them included a 2-year carcinogenicity assay. Most of the reviewed studies pointed out the potential of MNPLs to induce inflammation and genotoxicity, the latter being recognized as a strong predictor of carcinogenicity. These, along with other important findings such as the MNPLs’ ability to accumulate into cells and tissues, or their capacity to induce fibrosis, may suggest an association between MNPLs exposures and the carcinogenic potential. Nevertheless, the limited number of available studies precludes reaching clear conclusions. Therefore, this review also provides several recommendations to cover the current knowledge gaps and address the future evaluation of the MNPLs’ carcinogenic risk.

人们越来越关注持续接触环境微塑料和纳米塑料 (MNPL) 可能对人类造成的潜在健康影响。由于其持久性，MNPLs 可能会在不同的器官和组织中积累，并可能在长期内诱发癌症的发展。本研究旨在回顾有关 MNPL 致癌潜力的现有文献。由于预计直接评估致癌性的研究很少，因此在文献检索中考虑了处理与致癌过程相关的间接结果的研究。在筛选的 126 项研究中，有 19 项符合纳入标准。此外，通过仔细阅读先前选定的论文，确定了另外 7 篇交叉引用的文章也符合纳入标准，因此，被纳入审查。大多数选定的研究是使用体外模型，而大约 40% 的研究是在啮齿动物中进行的，尽管它们都没有包括 2 年致癌性试验。大多数经过审查的研究指出 MNPL 可能诱发炎症和遗传毒性，后者被认为是致癌性的有力预测因子。这些，连同其他重要发现，例如 MNPLs 积累到细胞和组织中的能力，或它们诱导纤维化的能力，可能表明 MNPLs 暴露与致癌潜力之间存在关联。然而，现有研究数量有限，无法得出明确的结论。因此，本综述还提供了一些建议，以弥补当前的知识差距并解决未来对 MNPL 致癌风险的评估。