Assessment of metal contaminants in non-small cell lung cancer by EDX microanalysis

Human cardio-respiratory diseases are strongly correlated to concentrations of atmospheric elements. Bioaccumulation of heavy metals is strictly monitored, because of its possible toxic effects. In this work, we utilized the EDX microanalysis in order to identify the potential heavy metal accumulation in the lung tissue. To this aim, we enrolled 45 human lung biopsies: 15 non-small cell lung cancers, 15 lung benign lesions and 15 control biopsies. Lung samples were both paraffin embedded for light microscopy study and epon-epoxid embedded for transmission electron microscopy. EDX microanalysis was performed on 100 nm thick unstained ultrathin-sections placed on specific copper grids. Our results demonstrated that the EDX technology was particularly efficient in the study of elemental composition of lung tissues, where we found heavy metals, such as Cobalt (Co), Chromium (Cr), Manganese (Mn) and Lead (Pb). Furthermore, in malignant lesions we demonstrated the presence of multiple bio-accumulated elements. In fact, a high rate of lung cancers was associated with the presence of 3 or more bio-accumulated elements compared to benign lesions and control tissue (91.7%, 0%, 8.3%, respectively). The environmental impact on pulmonary carcinogenesis could be better clarified by demonstrating the presence of polluting agents in lung tissues. The application of EDX microanalysis on biological tissues could shed new light in the study of the possible bioaccumulation of polluting agents in different human organs and systems.