人肺癌中TNF-α基因多态性分布的意义及其对细胞凋亡的影响

Study on associations between the polymorphism distribution of TNF - a gene and effect on it’s gene expression or apoptosis

目的:观察TNF-α基因启动子区-308位核苷酸多态性基因型在肺癌和对照人群中的分布,以及这种多态性对该基因表达和细胞凋亡的影响。方法:PER-RFLP分析112例肺癌和99例正常人的TNF-α基因启动子区-308位核苷酸多态性,TNF-α-308*G等位基因记做TNF-α1,TNF-α-308*A等位基因记做TNF- α2。免疫组织化学方法检测肺癌组织中TNF-α的表达,比较不同基因型肺癌病例的标本之间TNF-α基因表达的差异性。TUNEL法检测肺癌组织中细胞凋亡,并对比分析TNF-α-308位核苷酸多态性及其对肺癌组织中TNF -α表达和不同类型细胞凋亡的影响。结果:肺癌组与对照组的基因型分布为TNF-α1/1(52．7％、46．5％)。 TNF-α1/2(35．7％、48．5％),TNF-α2／2(11．6％、5．1％);等位基因频率为TNF-α1(70．5％、70．7％),TNF- α2(29．5％、29．3％),组间没有显著性差异,P】0．05。两种基因型个体在TNF-α基因表达上,TNF-α2/2基因型个体高于TNF-α1／1基因型的个体,两者差异显著,P【0．01。TNF-α表达的高低与癌细胞凋亡有比较明确的关系,TNF-α表达高的病例,肺癌细胞凋亡也多,与表达低的病例之间有明显差异,P【0．01。TNF-α表达的高低与间质细胞凋亡之间没有明确的关系。间质细胞平均凋亡指数在高、低分化的肺癌中分别为3．4±0．4和 3．1±0．5,组间没有显著性差异,P】0．015;癌细胞的平均凋亡指数在高、低分化的肺癌中分别为2．4±0．3和 1．7±0．4,两组间有显著性差异,P【0．05,,结论:TNF-α-308位核苷酸的多态性基因型在肺癌和正常人中的分布之间没有明显差别,这种多态性可能不是肺癌易感的遗传因素。但这种多态性与该基因的表达有关。TNF-α高表达肺癌细胞凋亡较多,间质细胞凋亡与TNF-α表达的高低变化之间没有明确的关系。在高分化的肺癌中, TNF-α表达较高,癌细胞凋亡也多,TNF-α-308位核苷酸的多态性可能与了肺癌的分化有关。

Objectives: To observe the distribution of polymorphism genotype of TNF - a gene promoter - 308 nucleotide in lung cancer and control groups, and its effects on expression of TNF- a gene and apoptosis. Methods: The polymorphism of TNF- a gene promoter - 308 nucleotide was analyzed by PGR - RFLP of 112 lung cancer patients and 99 control people.The expression of TNF - awas detected by immunohistochemistry assay. Cell apoptosis was detected by TUNEL methods, the effect of TNF - apolymorphism genotypes on expression of TNF - aand cell apoptosis were analyzed. Results: The distribution of genotype TNF- a1/1,1/2,2/2 were 52.7%.46.5%.35.7%.48.5%.11.6%.5.1% in patients group and control groups respectively; the frequency of allele TNF - a1, TNF - a2 were 70.5%.70.7%, 29.5% . 29.3% in patients group and control groups respectively, no obvious difference between two groups, P > 0.05. The expression of TNF - awas higherin lung cancer patients than that of the control, P < 0.01. The expression of TNF - a was not related to mesenchymal cell apoptosis, but relate to lung cancer cell apoptosis P < 0.01, they have positive relationship. Average number of mesenchymal cell apoptosis were 3.4±0.4 and 3.1±0.5, lung cancer cell apoptosis were 2.4±03 and 1.7±04 respectively. Conclusion: There are no significant difference of distribution of polymorphism of TNF- a gene promoter- 308 nucleotide in lung cancer patients and controls,this polymorphism isn’t genetic factor for lung cancer susceptibility,but it is related to the expression of it’s gene. The expression of TNF - a gene is related to apoptosis,the expression of TNF- a has a positive relation to lung cancer apoptosis,but to mesenchymal cell apoptosis. The higher expression of TNF - a, the more lung cancer cell apoptosis are. The polymorphism of TNF - a gene promoter -308 nucleotide may be related to lung cancer differentiation.