AIM: To investigate cytpchrome P4502E1 (CYP2E1) geneexpression in occurrence and progression of hepatocellularcarcinoma (HCC).METHODS: The human liver arrayed library was spottedonto the nylon membranes to make cDNA array.Hybridizationof cDNA array was performed with labeled probes synthesizedfrom RNA isolated from HCC and adjacent liver tissues.Sprague-Dawley rats were administrated diethylnitrosamine(DENA) to induce HCC.CYP2E1 expression was detected bythe method of RT-PCR and Northern blot analysis.RESULTS: CYP2E1 was found by cDNA array hybridizationto express differently between HCC and liver tissues.CYP2E1only expressed in liver,but did not express in HCC tissuesand expressed lowly in cirrhotic tissues.In the progressionof cirrhosis and HCC,the expression level of CYP2E1 wasgradually decreased and hardly detected until the late stageof HCC.CONCLUSION: Using arrayed library to make cDNA arraysis an effective method to find differential expression genes.CYP2E1 is a unique gene expressing in liver but did notexpress in HCC.CYP2E1 expression descended along withthe initiation and progression of HCC,which is noteworthyfurther investigations in its significance in the developmentof HCC. AIM: To investigate cytpchrome P4502E1 (CYP2E1) geneexpression in occurrence and progression of hepatocellular carcinoma (HCC) .METHODS: The human liver arrayed library was spottedonto the nylon membranes to make cDNA array. Hybridizationof cDNA array was performed with a labeled probe synthesizedfrom RNA isolated from HCC and adjacent liver tissues. Sprague-Dawley rats were administered diethylnitrosamine (DENA) to induce HCC. CYP2E1 expression was detected by the method of RT-PCR and Northern blot analysis. RESULTS: CYP2E1 was found by cDNA array hybridization to express different between HCC and liver tissues . CYP2E1 fully expressed in liver, but did not express in HCC tissues and expressed lowly in cirrhotic tissues. In the progression of cirrhosis and HCC, the expression level of CYP2E1 wasgradually decreased and hardly detected until the late stage of HCC .CONCLUSION: Using arrayed library to make cDNA arraysis an effective method to find differential expression genes. CYP2E1 is a unique gene expr essing in liver but did notexpress in HCC. CYP2E1 expression descended along with the initiation and progression of HCC, which is noteworthyfurther investigations in its significance in the development of HCC.