54 Erionite-induced carcinogenicity: mechanistic insights and comparative potency with asbestos

Abstract Erionite (CAS No. 66733-21-9) is a naturally occurring fibrous zeolite with mesotheliogenic potency greater than that of asbestos minerals. However, unlike asbestos, erionite has rarely been used for commercial purposes, and as a result, information on exposure pathways remains limited. Numerous experimental animal studies evaluating the carcinogenic potential of erionite have produced a high incidence of mesotheliomas across routes of administration, and epidemiological studies have demonstrated elevated mesothelioma mortality in populations exposed to erionite. Although the carcinogenicity of erionite is well established, the underlying mechanisms remain poorly defined. The purpose of this analysis is to synthesize and critically evaluate the experimental, mechanistic, and epidemiological evidence on the human health hazards associated with erionite exposure, with emphasis on biological mechanisms driving its mesotheliogenic potency. Across experimental systems, erionite has demonstrated equal or greater potency than asbestos in inducing mesothelioma. It produces concentration-dependent cytotoxicity in human and rodent cell types, along with genotoxic and cell-transforming effects indicative of DNA damage and mutagenic stress. Persistent macrophage activation, generation of reactive oxygen and nitrogen species, and sustained inflammatory signalling have been identified as key mediators of chronic tissue injury and tumorigenesis. These responses are further modulated by structural iron and other physicochemical characteristics, including redox cycling and enhanced surface reactivity. Erionite’s fibrous morphology, high aspect ratio, and remarkable biopersistence collectively underpin its pronounced mesotheliogenic potential relative to asbestos. Collectively, these interrelated processes position erionite among the most potent mineral fibres known, inducing mesothelioma through convergent pathways involving inflammation, oxidative stress, and genotoxic damage.