湖南人群CYP1A1、GSTM1、GSTT1基因多态性与急性白血病易感性关系研究

目的分析生物代谢酶Ⅰ相酶细胞色素P4501A1（CYP1A1）和Ⅱ相酶谷胱甘肽转硫酶GSTM1、GSTT1基因的遗传多态在湖南人群急性白血病患者和健康人群中的分布。方法采用病例对照研究方法，应用聚合酶链反应及聚合酶链反应-限制性片段长度多态性技术对112例急性淋巴细胞性白血病（ALL）患者和120例急性非淋巴细胞性白血病（ANLL）患者以及204名健康个体的CYP1A1 MspⅠ多态（3801 T—C突变）、GSTM1和GSTT1等基因的多态分布进行分析。结果ALL组与ANLL组的CYP1A1基因3801位点等位变异的频率分别为74．1％、70．8％，高于对照组（63．3％），但其差异无统计学意义（P〉0．05）；ALL组GSTM1缺失基因型（GSTM1-／-）的频率为60．7％，与对照组（55．4％）比较差异无统计学意义（P〉0．05）；ANLL组GSTM1-／-基因型频率为68．3％，与对照组比较差异有统计学意义（P〈0．05）。ALL组、ANLL组及对照组的GSTT1缺失基因型（GSTT1-／-）的频率分别为50．9％、55．0％和49．0％，病例组与对照组差异无统计学意义（P〉0．05）。GSTM1-／-和GSTT1-／-联合基因型在ALL、ANLL患者组和对照组中的频率分别为33．0％、40．0％和27．5％，其中ANLL组与对照组比较，其差异有统计学意义（P〈0．05）。同时携带CYP1A1 MspⅠ多态突变基因型（杂合突变型或纯合突变型）与GSTM1-／-、GSTT1-／-基因型的个体患ANLL的风险增加（OR=1．890，95％CI：1．084～3．295）。结论单一的CYP1A1 MspⅠ多态突变基因型或GSTT1-／-基因型与急性白血病易感性不相关；GSTM1-／-基因型及其与GSTT1-／-基因型、CYP1A1 MspⅠ多态突变基因型（杂合突变型或纯合突变型）同时存在时增加患ANLL的风险。提示GSTM1-／-可能是ANLL发病的易感因素之一，且与其他缺陷基因型存在协同作用。

Study on the relationship between polymorphisms of CYP1A1, GSTM1, GSTT1 genes and the susceptibility to acute leukemia in the general population of Hunan province

OBJECTIVE: Based on the distribution of genetic polymorphisms regarding phase I metabolic enzyme cytochrome P450 1A1 (CYP1A1) and phase II metabolic enzymes glutathione S-transferase GSTM1 and GSTT1 genotypes in acute leukemia patients and health controls among general population of Hunan in China, this study was to explore the relationship between these gene polymorphisms and the susceptibility to acute leukemia. METHODS: Using case-control methodology, we studied 204 healthy controls and 232 patients with acute leukemia, of which 112 patients were suffering acute lymphoblastic leukemia (ALL) and 120 with acute non-lymphoblastic leukemia (ANLL). The frequencies of the genotypes were detected by PCR and PCR-RFLP techniques. RESULTS: The variation frequencies of CYP1A1 gene (Msp I polymorphisms, site 3801T-C variation) in ALL and ANLL groups were 74.1% and 70.8% respectively which were higher than 63.3% appeared in the healthy controls. However, the differences between patients (ALL or ANLL) and healthy controls were not statistically significant (P > 0.05 for both). The null genotype of GSTM1 (GSTM1 -/-) in ALL group was 60.7%, which was not significantly different from the controls (55.4%). However, GSTM1 -/- genotype in ANLL group was 68.3%, significantly different from the controls (P < 0.05). The null genotypes among GSTT1 (GSTT1 -/-) in ALL, ANLL and control group were 50.9%, 55.0% and 49.0% but their differences were not statistically significant (P > 0.05). The incidences of GSTM1 -/- and GSTT1 -/- combined genotype in ALL, ANLL and control group were 33.0%, 40.0% and 27.5%, of which the difference between ANLL group and control group was statistically significant (P < 0.05) and CYP1A1 gene heterozygous mutation type or homozygous mutation type combined with GSTM1 -/- and GSTT1 -/- increased the risk of ANLL (OR value 1.890, 95% CI: 1.084-3.295). CONCLUSION: These results indicated that both the variation of CYP1A1 gene or GSTT1 -/- genotype alone might not be associated with the susceptibility of acute leukemia while GSTM1 -/- genotype alone or combined with GSTT1 -/- or the 3801 T-C variation of CYP1A1 gene were correlated with ANLL. These findings suggest that GSTM1 - / - genotype alone or in combination with other defective genotypes might serve as risk factors to the etiology of ANLL.