OBJECTIVES: To study the mutation of beta-catenin 、 p53 gene and the alternative splicing of DNMT3b、 hTERT gene in primary hepatocellular carcinoma, and their effects on the development of hepatocellular carcinoma.METHODS: 29 RT products for p53 gene, 18 for beta-catenin gene, 38 for DNMT3b, 17 for hTERT. PCR、 T-A clone 、 DNA sequencing andoligonucleotide chip were used to detect them.RESULTS: PCR showed that the expression of beta-catenin gene wasdetected in 85. 7%(6/7)of HCC 、 100%(11/11)of para-cancerous tissues . p53 gene expression was detected in 69. 2%(9/13)of HCC 、 81. 3%(13/16)of para-cancerous tissues .There was no signif icantdifference in HCC than in para-cancerous tissues . DNMT3b gene expression was detected in the forms of alternative spliced variant(DNMT3bl 、 DNMT3b3 、 DNMT3b4 、 DNMT3b5), their total expression were 92.3%(12/13) in HCC、 71. 4%(10/14) in para-cancerous tissues and 90.9%(10/ll) in nomal and chronic liver diseases tissues. DNMT3bl expression was higher in nomal and chronic liver diseases tissues than in HCC. DNMT3b4 expressed in one of HCC and one of para-cancerous tissues, DNMT3b5 expressed in one of para-cancerous tissues, all of them have not expression in nomal and chronic liver diseases tissues. hTERT gene expression was detected in the forms of alternative spliced variant(full-length transcripts 、 α -splicing variant, β -splicing variant, and α β-splicing variant), their totalexpression were 90%(9/10) in HCC , 100%(4/4) in para-cancerous tissues and 66. 7%(2/3) in normal and chronic liver diseases tissues. There was no significant difference among the three groups. The expression ratio of full-length transcripts was 66.7% in HCC> 25% in para-cancerous tissues , 0 in normaland chronic liver diseases tissues. Although there was no significant difference among the three groups, but there was an increased tendency from the normaland chronic liver diseases tissues, para-cancerous tissues to HCC. DNA sequencing showed the mutation ratio of beta-catenin gene was 0(0/5) in HCC , 36.4% (4/11) in para-cancerous tissues, there was no significant difference . The mutation sites were code 14, 72, 80. The mutation ratio of p53 gene was 66. 7%(4/6) in HCC, 50% (5/10) in para-cancerous tissues and the mutation sites were code 232, 234, 235, 236> 244, 248, 258, 259, 273, 275, 279, 305. Using Oligonucleotide chip hybridization , no mutation was detected in all designed sites based on the reports of p53 gene . The signals corresponding to 4 alternative variants of DNMT3b gene and hTERT gene were all detected.CONCLUSIONS: The mutation ratio of Beta-catenin gene was low .The reasons were the cases were not enough and maybe there were some other ways to act Wnt passway. The mutation ratio of p53 in HCC was 66. 7%(4/6), the mutation sites focused in the 5 conservative areas. DNMT3b have 4 alternative variants , DNMT3bl may play an important role in maintain the function of DNMT. hTERT have 4 alternative variants , the expression of full-length transcripts of hTERT .have an increasedtendency from the normaland chronic liver diseases tissues > para-cancerous tissues to HCC.