Abstract: BACKGROUD ＆ AIM: To explore the malignant transformation effects of Yunnan tin mine dust on human bronchial epithelial cells, further investigate the cause and mechanism of lung cancer in Yunnan tin miners. MATERIAL AND METHODS: The immortalized human bronchial epithelial cells BEAS-2B were treated with tin mine dust at the concentrations of 200 μg/ml and 50 μg/ml for 72 hours on every other generation and was stopped in the 9 th generation, including a negative control group. The characteristics of the cellular biology and the malignant transformation phenotype of cells were identified through observing serum resistance, anchorage independent growth, etc. RESULTS: Each group of cells in the 20 th generation didn't show serum resistance. For the high mine dust concentration group cells in the 25 th generation, the multiplication time, the serum resistance and the aberration of chromosome were increased, with the formation of small cell colonies in soft agar in the 30th generation. The anchorage independent growth appeared in high and low concentration groups in the 40th generation. CONCLUSONS: Tin mine dust in Yunnan province could induce malignant transformation of BEAS-2B cells.By passing generation and selection in soft agar medium we established the pre-cancerous transformation cells that could be cultured long term in vitro.

Key words: Human bronchial epithelial cells, BEAS-2B, Tin mine dust, Malignant transformation