PTPN11第3内含子基因多态性与胃癌的相关性研究

Correlation of PTPN11 polymorphism at intron 3 with gastric cancer

目的研究中国汉族人群中蛋白酪氨酸磷酸酶非受体型11(PTPN11)第3内含子基因的rs2301756位点多态性与胃癌发生的相关性,并探讨基质辅助激光解吸电离-飞行时间质谱技术(MALDI-TOF-MS)检测此多态性的可行性与准确性。方法采用MALDI-TOF-MS对中国汉族的247例胃癌、212例非癌患者以及160例脐带血的PTPN11基因第3内含子rs2301756多态性位点进行基因分型,并用PCR产物直接测序技术对该位点的20例样本进行分型,以验证MALDI-TOF-MS技术的准确性。应用组织涂片镜检、幽门螺杆菌(H.pylori)培养、快速尿素酶、ELISA和胶体金法等5种方法来检测受试者的H.pylori感染情况。结果 20例样本PTPN11第3内含子基因rs2301756位点MALDI-TOF-MS技术分型结果与测序结果完全相符,两种方法的基因型分型结果具有很好的一致性。胃癌组和非癌对照组H.pylori(+)者分别为182例(73.68%)和160(75.47%)。H.pylori感染率在两组间无明显差异(P>0.05)。胃癌组和非癌对照组PTPN11基因在该位点的基因型频率分布符合遗传平衡状态。将G/A型和A/A型合并后与G/G型相比,带有A等位基因的个体不能影响胃癌的发生风险。根据年龄、性别、H.pylori感染对胃癌的易感性进行的分层分析发现,PTPN11基因该位点SNP与年龄、性别和H.pylori感染状态无关。结论中国汉族人群PTPN11基因第3内含子rs2301756位点SNP与胃癌发病风险无关。

Objective To explore the correlation of protein-tyrosine-phosphatase nonreceptor-type 11（PTPN11） polymorphism at intron 3 with gastric cancer in Chinese population,and the feasibility and accuracy of employing mastrix-assisted laser desorption ionization time-of-flight mass spectrogram（MALDI-TOF-MS） in genotyping of this SNP.Methods Two hundred and forty-seven patients with gastric cancer,212 cancer-free patients and 160 cord blood samples were enrolled in present study.Genotypes of PTPN11 G/A polymorphism at intron 3 were determined by MALDI-TOF-MS analysis,and direct sequencing of PCR products with 20 samples of the gene locus was done for checking the accuracy of MALDI-TOF-MS.Histological examination,Helicobacter pylori culture,rapid urease test,serum anti-H.pylori antibodies（ELISA） and urease colloidal gold test were performed to evaluate H.pylori infection.Results Direct sequencing of 20 random selected samples were well consistent with the MALDI-TOF-MS results.The rates of H.pylori infection were 73.68% in gastric cancer patients and 75.47% in cancer-free patients,implying no significant difference between the two groups.The distributions of genotypes were in Hardy Weinberg equilibrium in both gastric cancer patients and controls.There were no significant differences in the genotype frequencies between the 2 groups（P〉0.05）.Compared with the GG genotype,GA＋AA genotype could not influence the risk of gastric cancer.When stratified for status,PTPN11 polymorphism was not associated with age,gender and H.pylori infection states in both cancer patients and controls.Conclusion It seems that PTPN11 G/A polymorphism at intron 3 has no affection on the risk of gastric cancer in Chinese population.