Exposure to inorganic arsenic and gene expression in peripheral blood

Arsenic is an established carcinogen and a risk factor for several non-malignant diseases. Mechanisms of arsenic toxicity may include interference with gene expression. The impact of arsenic exposure on gene expression was evaluated in women (n = 80) living in the Puna of the northern Argentinian Andes with varying concentrations (10–1251 μg/L) of arsenic in drinking water. DirectHyb HumanHT-12 v4.0 was used for genome wide gene expression analysis. Robust linear regression model was used to each array to evaluate the relations between arsenic exposure, gene expression and with the influence of arsenic metabolism efficiency. Also, Ingenuity Pathway Analysis (IPA) was performed to look for relevant pathways, diseases, networks etc. associated with the genes. In the association between arsenic and gene expression, most of the genes were downregu-lated. Pathway analyses revealed different expression pattern associated with arsenic exposure between women with high and low urinary %MMA, indicating variation in arsenic susceptibility by arsenic-methylation.