RISK ASSESSMENT OF NICKEL CARCINOGENICITY AND OCCUPATIONAL LUNG-CANCER

Recent progress in risk assessment of nickel carcinogenicity and its c orrelation with occupational lung cancer in nickel-exposed workers is reviewed. Epidemiological investigations provide reliable data indicat ing the close relation between nickel exposure and high lung cancer ri sk, especially in nickel refineries. The nickel species-specific effec ts and the dose-response relationship between nickel exposure and lung cancer are among the main questions that are explored extensively. It is also suggested that some confounding factors such as cigarette smo king cannot be neglected. The determination of nickel concentration in lung tissue may be conducive to estimating the nickel exposure level, but it is uncertain whether the high nickel content in lung tissue in dicates high lung cancer risk in nickel-exposed workers. Immunologic s tudies suggest that the suppressive effect of nickel on NK cell activi ty and interferon production may also be involved in the mechanisms of nickel carcinogenesis. As a potential mutagen, nickel can cause chrom osome damage both in vitro and in vivo; and on a molecular basis, nick el is found to induce DNA damage (DNA strandbreaks and crosslinks, inf idelity of DNA replication, inhibition of DNA repair, and the helical transition of B-DNA to Z-DNA) by binding of nickel ions to DNA and nuc lear proteins. The discovery of oncogene promises both a challenge and an opportunity for nickel carcinogenesis research. It can be predicte d that, with the rapid development of molecular biology and oncology, new approaches will be established for both understanding and controll ing nickel-induced occupational lung cancer.