Metallic elements in pulmonary biopsies from lung cancer and control subjects

Occupational/environmental exposure to some metallic elements is a risk factor for the development of lung diseases, including lung cancer. We aimed at investigating the levels of arsenic, beryllium, cadmium, cobalt, chromium, nickel and lead in the lung tissue of patients affected by early stage non small cell lung cancer (NSCLC). A small number of patients without a diagnosis of lung cancer were also included as control group. Lung tissue biopsies were collected from 45 NSCLC patients (both cancerous and unaffected tissues) and 8 control subjects undergoing surgery. Patients were stratified for smoking habits, histopathology and cancer sites. Metallic elements were determined in dry tissue after digestion by means of ICP-MS. Cd, Ni and Pb levels were higher in unaffected than in control tissues (0.52 vs 0.18 microg/g dry, p < 0.05 for Cd; 4.49 vs 1.8 microg/g dry,p < 0.05 for Ni; 0.21 vs 0.06 microg/g dry, p < 0.01 for Pb). The three elements, and particularly Cd, were influenced by smoking habits; Pb levels were higher in squamocellular carcinoma than adenocarcinomas; Ni distributed in the lungs in an inhomogeneous way. This study demonstrates that the unaffected lung tissue is more representative than the cancerous tissue of the pulmonary content of metallic elements. Tobacco smoke is a main factor affecting the concentration levels of Cd, Pb, and to a lesser extent Ni in the lung tissues of NSCLC patients. The role of past environmental-occupational exposures could not be fully elucidated, due to the limited sample size and the retrospective nature of the study.