Role of Environmental Toxicants and their exposure in the Etiology of Cancer

Abstract

Cancer, a leading cause of morbidity and mortality worldwide, is a concerning disease with its multifaceted causality. Substantial contributors to the etiology of cancers are environmental factors. Environmental toxicants, including pesticides, heavy metals, air pollutants, persistent organic pollutants, and emerging contaminants such as microplastics, are ubiquitous in modern ecosystems and human environments. Exposure to these toxicants over a long period of time, even at minimal doses, has been strongly linked to carcinogenesis through diverse molecular and cellular mechanisms. This review summarizes current evidence on sources and routes of exposure to environmental toxicants and critically examines their role in cancer etiology. Key mechanisms suchas genotoxicity, oxidative stress, epigenetic dysregulation, endocrine disruption, and immune modulation are discussed. Epidemiological and experimental findings supporting the association between toxicant exposure and site-specific cancers are highlighted. Emerging concepts, including the exposome, cumulative risk assessment, and gene–environment interactions, are also addressed. Understanding the contribution of environmental toxicants to cancer development is essential for risk assessment, preventive strategies, and public health policy formulation.