[Experimental study on induction of lung cancer in hamster by fifteen chemical elements in the industrial dust from Yunnan Tin and other mines].

To exclude the carcinogenicity of trace radioactive elements in the mine powder and flue dust and clarify those inorganic chemical elements related to carcinogenesis of lung cancer, 15 non-radioactive inorganic chemical elements (CM1) responsible for mutagenesis, tumorigenesis and promotion of cancer from mine powder and flue dust were mixed for Ames test and carcinoma-inducing-experiment in animals. The results were as follows: 1. Ames test of CM1 showed positivity. 2. Lung cancer-inducing-experiment of CM1 in the hamster was successful with an incidence of 8.8% whereas in the control group, no lung cancer developed which showed that CM1 was related to the development of lung cancer. 3. Hyperplastic cells under light microscope showed Type II alveolar cells and Clara cells under electron microscope. It is possible that hyperplastic, precancerous and malignant cells in the lung are derived from these two kinds of cells. One case of multiple microcarcinoma was found in this experiment.