Objective   Nickel, chromium, and other metal poisons are confirmed as chemical carcinogens to human.The effects of nickel, chromium and other metal poisons on the development of human lung cancer are investigated.

  Methods   55 lung cancer patients tumor specimens and 23 normal lung tissues from benign lung lesion cases and accidental deaths are collected.The metal poisons like cadmium(Cd), chromium(Cr), nickel(Ni), lead(Pb), beryllium(Be), and metalloid arsenic(As) are detected by Inductively Coupled Plasms-Atomic Emission Spectrometry(ICP-A ES).The specimens are stratified by cell types and smoking status.These metal poisons are also detected in tumorous tissues from nude mice inoculated with human bronchial epithelial cells which are transformed by sulfide nickel(NiS)and BPDE(anti-Benzo(a)pyrene diol-epoxide) in vitro.

  Results   Some kinds of metal poisons are determined in the lung tissues of general population.Ni content is higher in lung cancer specimens than that in normal lungs(10.5172±2.6739)μg/g dried lung tissue(mean+/-SD)versus(4.121 8±2.175 2)μg/g, t=10.14, P < 0.01.Similar tendency is found in Cr content, i.e.(7.690 6±3.101 2)μg/g versus(4.124 4±2.753 8)μg/g t=5.04, P < 0.01.In smokers, Ni and Cr content are higher than that in non-smokers, P < 0.05.In squamous cell carcinoma, Ni content is higher than that of adenocarcinoma(12.560 9±2.345 5)μg/g versus(8.237 7±2.782 8)μg/g, t=6.25, P < 0.01.Transformation of human bronchial epithelial cells are induced by sulfide nickel(NiS)and BPDE in vitro.The transformed cells were injected to nude mice, and grow as tumorous tissues.Nickel content in nude mice's tumor from NiS treated cells is 4.3 times higher than that from BPDE transformed cells(21.00μg/g versus 4.88μg/g dried tumor tissue).

  Conclusion   Nickel, chromium and other metal poisons are the risk factors of human lung cancer.Smoking is an important un-occupational exposure to metal poisons.