METAL CONCENTRATIONS IN LUNG-TISSUE OF SUBJECTS SUFFERING FROM LUNG-CANCER

Concentrations of nine metals (Fe, Ca, Mg, Zn, Cu, Co, Ni, Pb and Cr) concentrations in lung tissues from 224 lung cancer cases were compared with those in other cases to achieve an understanding of their contribution to the development of lung cancer and the varieties after the development of cancer. Comparisons of metal concentrations in each cell type of lung cancer were also performed. All cases were collected from routine autopsies in Tokyo and Saitama, Japan. The copper concentration in tissue from lung cancers was significantly higher than that in other specimens, although calcium, magnesium, zinc and cobalt concentrations in lung cancers were significantly lower than those in other cases. There were no significant differences in the 99% intervals (excluding extremely high values for occupationally exposed cases) for chromium, nickel and lead concentrations between lung cancers and other cases, although these values were lower in lung cancers. However, in comparisons of men only, the chromium concentration, the degree of lung contamination and the severity of pulmonary emphysema in lung cancer cases were significantly higher than those in other specimens. Moreover, percentages of lung cancer in men at each degree of contamination and each severity of emphysema increased with increasing grades. Thus, this finding could be evidence that the exposure to contaminants other than chromium and nickel in the air had affected the development of lung cancer, except for occupationally exposed individuals. Therefore, almost all chromium and nickel in lung tissue might not deposit in carcinogenic forms such as hexavalent chromium or nickel subsulfide. Comparison of the characteristics in each cell type of lung cancer revealed that calcium and chromium concentrations in lung tissue (not including tumor) or squamous cell carcinomas were higher than those in the other cell types. In small cell carcinomas, calcium magnesium and zinc concentrations were low.