胃癌易感性与细胞毒性T淋巴细胞相关抗原-4基因＋49A／G多态性的关系

Association of cytotoxic T lymphocyte antigen-4 gene ＋ 49 A/G polymorphism with susceptibility of gastric cancer

目的探讨细胞毒性T淋巴细胞相关抗原-4（CTLA-4）基因外显子1区＋49A／G位点多态性在中国人群中的分布及其与胃癌易感性的关系。方法应用聚合酶链反应-限制性片段长度多态性（PCR—RFLP）方法检测205例胃癌患者和262例正常对照者CTLA-4基因＋49A／G多态位点基因型频率，进行多态性与胃癌易感性的关系分析并进行分层分析。结果CTLA-4基因外显子1区＋49位点A／G、G／G基因型在胃癌组患者中的分布频率明显高于对照组（P〈0．01，OR=2．146；P〈0．01，OR=3．215）；分层分析示：男性患者、年龄在40～55岁之间、不吸烟、不饮酒患者组等组别的胃癌患者携带G／G基因型的频率较正常对照组显著增加。结论CTLA-4基因外显子1区＋49A／G多态性与胃癌易感性有明显相关，携带A／G、G／G基因型的个体胃癌发病风险增加，分层因素也影响这一结果。

Objective To investigate the distribution of ＋49A/G polymorphism of CTLA-4 gene in Chinese population and the association between the polymorphism and susceptibility of gastric cancer. Methods Unrelated 205 patients with gastric cancer and 262 healthy controls were enrolled, polymerase chain reaction-restriction fragment length polymorphism （PCR-RFLP） was used to determine genotype frequencies of ＋ 49A/G polymorphism. The association of the polymorphism with relevant risk factors of gastrie cancer was analyzed. Results The distribution of ＋ 49A/G gene polymorphism was in accordance with Hardy-Weinberg equilibrium. The A/G and G/G genotype frequencies in the patients were significantly higher than those in controls （ P 〈 0.01, OR = 2. 146 ; P 〈 0.01, OR = 3. 215 ） ; Stratified by clinical characters ： men, or age between 40 and 55, or without smoking or drinking in patients with gastric cancer carried more G/G genotype than the controls. Conclusion CTLA-4 ＋ 49A/G polymorphism might be a predisposing factor of gastric cancer.