Abstract: ObjectiveTo investigate the role of mutations of P53 gene in the atypical hyperplasia of bronchus epithelia and carcinogenesis of lung.MethodsImmunohistochemistry staining was used to detect the expression of mutated P53 protein in 41 cases of bronchus epithelium tissues,150 cases of lung cancer tissues and 51 cases of normal lung tissues.PCR amplification and DNA sequencing were used to assay the mutaion of P53 gene in the BPDE transformed human bronchial epithelium cells.ResultsThe expression rate of mutated P53 protein was 7.8% (4/51)in normal lung tissues,43.90% (18/41)in atypical hyperplasia of bronchus epithelium tissues,and 68.7% (103/150)in lung cancer tissues,the difference between different tissues was highly significant(P<0.01),and there was a trend for expression of mutated P53 from normal lungs to atypical hyperplasia of bronchus eithelium,and to lung cancer(P<0.001).The expression of mutated P53 were higher in the smokers than that of non-smokers.The mutated P53 protein and mutaion in the sequence of P53 gene were detected simultsneously in BPDE transformed human bronchial epithelium cells.ConclusionThe mutation of P53 is associated with lung carcinogenesis,smoking exposure can cause P53 mutation,and the detection of mutation in P53 gene will be helpful for the early diagnosis of human lung cancer.