Arsenic-induced Cancers : A Review with Special Reference to Gene, Environment and Their Interaction

Chronic exposure to the toxic metalloid arsenic, either through occupational or environmental route results in the development of a plethora of dermatological as well as non-dermatological health eSects, multi-organ cancers being the most severe ones. Several epidemiological studies have reported the occurrence of diSerent types of cancers in populations exposed chronically to arsenic from diSerent corners of the globe, but the spectrum of symptoms and severity vary widely. Several genetic and environmental factors might play an important causal role for such observed diSerences, including genetic polymorphisms, dietary habits and socio-economic status of the population. Unfortunately, the paradoxical nature of this carcinogen makes the use of animal model systems unsuitable, since they do not re‰ect the exact in vivo condition of arsenic exposure in human beings. Hence, in this present review, we have attempted to collate the isolated pieces of information available in existing literature depicting the various forms of arsenic-induced cancers, variations and etiology thereof. We have attempted to depict the entire spectrum of carcinogenic outcomes of chronic arsenic exposure and the interactions among several components like, genes (polymorphisms and mutations), environmental factors and dietary factors in the process. The literature reviews are primarily based on the human beings (in vivo), but to understand the underlying mechanism, we have also collated the information based on cell line models, and animal models where human data is scanty or unavailable. Thus, here we present a comprehensive review on the current state of research in the ˆeld of arsenic-induced cancer and explore the underlying mechanism of arsenic-induced carcinogenicity, along with relevant historical perspective.