AIM: To investigate the effect of ethanol and chemical carcinogen N,N'-dinitrosopiperazine(DNP) on the exogenous expression of CYP2E1.METHODS: Exogenous hCYP2E1 was introduced into NIH3T3 mediated by lipofectamine. Then the integration of exogenous gene was showed by Southemrn blot. After treated with different concentration of ethanol and DNP,RT-PCR and Western blotting were used to analyze the expression change of hCYP2E1 in NIH 3T3. RESULTS: Two cell clones with integration and stable expression of exogenous hCYP2E1 were obtained. The RT-PCR and Western blotting showed that human CYP2E1 mRNA and protein expression was enhanced with increase in ethanol and DNP concentration. CONCLUSION: Exogenous expression of hCYP2E1 was steadily induced by ethanol and DNP. The mechanism may be due to the activation of its transcription. The DNP carcinogenesis might be related to its in situ activation by CYP2E1.