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目的探讨γ谷氨酰转移酶（ＧＧＴ）基因在人类肝癌发生过程中的表达及改变机制。方法以病理组织学、生物化学和分子生物学方法，将自身配对的肝癌、癌旁组织和远癌组织中总ＲＮＡ纯化，对ＧＧＴ的表达与改变进行了分析；并设计两套引物，以逆转录巢式ＰＣＲ法扩增ＧＧＴ５′非编码区（ＮＣ）基因和限制性内切酶消化分析了不同肝癌组织中ＧＧＴ基因的甲基化程度。结果在病理组织学证实的２４例肝癌、癌旁和远癌组织中：①从肝癌灶至远癌的不同组织中，总ＲＮＡ浓度呈逐步升高趋势，三种不同组织间的差异均有显著性（Ｐ＜０．０５）；②癌组织中总ＧＧＴ比活性（Ｕ／ｇ）较癌周和远癌组织明显升高（Ｐ＜０．０５）；③以自行设计建立的逆转录巢式ＰＣＲ法，成功地扩增ＧＧＴ的５′ＮＣ基因片段，特异性强且区带清晰，ＰＣＲ产物经酶切分析证明，ＧＧＴ基因５′ＮＣＭ３位点（ＣＣＧＧ），其内位Ｃ在癌灶、癌周和远癌组织中的低甲基化频率分别为７０．８３％，５８．３３％和５４．１７％，非常明显地高于同组中已甲基化程度。结论肝癌组织中ＧＧＴ基因甲基化程度较低，且与肝癌ＧＧＴ的异常表达关系密切，对肝细胞癌变可能起促进作用。
Objective To investigate the expression and mechanism of γ-glutamyltransferase (GGT) gene in human liver cancer. Methods Total RNA was purified from histologically matched hepatocellular carcinoma, paracancerous tissue, and distant cancer tissue by histopathology, biochemistry, and molecular biology methods. The expression and changes of GGT were analyzed; two sets of primers were designed to reverse The GGT5′non-coding region (NC) gene was amplified by nested PCR and digested with restriction enzymes to analyze the degree of methylation of GGT gene in different HCC tissues. Results In histopathologically confirmed 24 cases of hepatocellular carcinoma, paracancerous and distant cancerous tissues: 1 The total RNA concentration gradually increased from the hepatocellular carcinoma to the distant carcinoma, and the differences among the three different tissues were significant. Sex (P<0.05); 2 The total GGT specific activity (U/g) in cancer tissue was significantly higher than that in the cancerous and distant cancer tissues (P<0.05); 3 The retroviral nested PCR method was designed and established. The successful amplification of the 5′-NC gene fragment of GGT is characterized by a strong specificity and a clear band. The PCR product proved by enzymatic analysis that the GGT gene 5′NCM3 (CCGG) has its internal C in the foci, The frequencies of hypomethylation in cancerous and distant cancer tissues were 70.83%, 58.33%, and 54.17%, respectively, which were significantly higher than those in the same group. Conclusion The degree of methylation of GGT gene in hepatocellular carcinoma is low, and it is closely related to the abnormal expression of GGT in hepatocellular carcinoma. It may play an important role in the carcinogenesis of hepatocellular carcinoma.