Role of chromium enriched tobacco in the occurrence of oral carcinogenesis

Abstract

Cancer is a disease of major concern grasping the entire globe. It is one of the diseases characterized by high rates of incidence and mortality. Among all the cancer types, oral cancer has a high occurrence in countries like India, where people are more inclined towards the use of tobacco either for smoking or for chewing purpose. Nicotianatabacum being a hyperaccumulator plant can thus accumulate high amount of heavy metals in its parts, mostly leaves. The carcinogenicity of tobacco may be linked to the high concentrations of metals present in it. The presence of chromium in the trivalent or Cr(III) form in the leaves of the tobacco plant is ignored assuming it to be non-toxic. However, smoking or chewing tobacco can lead to the conversion of Cr(III) to the toxic Cr(VI) as hypothesized in the current review. The paper in its current form discusses the process of aggregation of chromium in the above-ground parts of the tobacco plant. The rhizospheric factors that promote the metal uptake by the plant are also discussed. The notion that Cr in tobacco is harmless has been argued upon. The paper proposes the role of Cr enriched tobacco in causing oral cancer and predicts the probable underlying mechanism. It emphasizes on the need to regulate rhizospheric factors, to prevent the accumulation of high concentration of the toxic heavy metal in the biomass of the tobacco plant.