黑色素瘤抗原-A1基因多态性及其在肝癌组织中的表达

目的了解黑色素瘤抗原(MAGE)-A1基因在肝癌组织中的表达状况,探讨该基因是否存在单核苷酸多态性(SNP).方法用RT-PCR方法检测49例原发性肝细胞性肝癌(HCC)患者肝癌组织MAGE-A1基因mRNA的表达情况,同时提取其中43例HCC患者的肝癌组织、癌旁组织及外周血细胞基因组DNA,PCR扩增MAGE-A1 DNA,并对上述PCR产物进行测序.结果49例患者中MAGE-A1 mRNA阳性22例,阳性率44.9%.43例HCC患者癌组织、癌旁组织和外周血细胞中扩增的KAGE-A1 DNA序列测定显示MAGE-A1基因存在两类变异:TAG有16例,变异发生率为37.2%,包括3个位置的变异:C159T,A272G,G393A,GTG变异有7例,发生率为16.3%,亦包括3个位点的变异即:A272G,C991T,A1125G.因为C991T没有改变编码的氨基酸,A1125G不在编码区,故仅A272G引起一个氨基酸的替换(T32A).结论MAGE-A1在HCC中高表达,表达率为44.9%.MAGE-A1 mRNA的表达与AFP无关.MAGE-A1基因存在三种SNP,但不影响其mRNA的表达.

Analysis of polymorphism of MAGE-A1 gene and its expression in hepatocellular carcinoma tissues

Objective To investigate the expression of MAGE-A1 gene in hepatocellular carcinoma (HCC) and if there were single nucletide polymorphisms (CSNP) in MAGE-A1 gene.Methods RT-PCR was used to examine the expression of MAGE-A1 mRNA in tumor tissues of 49 HCC patients. The PCR products were sequenced directly. Genomic DNAs were extracted from cancerous, paracancerous tissues, and peripheral blood cells of 43 HCC patients. PCR amplification of MAGE-A1 DNA and sequencing the PCR products were performed.Results MAGE-A1 was expressed in 22 of 49 tumor tissues (44.9%) of HCC patients in mRNA level. 43 PCR products from genomic DNA were sequenced and two kinds of polymorphisms were found. One was found in 16/43 (37.2%) cases with three nucleotide acid changes (C159T, A272G and G393A), and was named as TGA polymorphism. This kind of polymorphism resulted in the substitution of two amino acid residues (T32A and R72Q). The other was found in 7/43 patients with three nucleotide acid changes (A272G, C991T and A1125G), and was named as GTG polymorphism, which resulted in one amino acid residue changed (T32A). Conclusion The expression rate of MAGE-A1 gene in human hepatocellular carcinoma is 44.9%. There are three polymorphisms of MAGE-A1 gene involved in SNP, which include the wild type of MAGE-A1 gene. The rate of MAGE-A1 expression has no relation to AFP value and polymorphism.