【摘要】 背景与目的:丝氨酸羟甲基转移酶(serinehydroxymethyltransferase,SHMT)是叶酸代谢过程中的关键酶,它通过为嘌呤、胸苷酸、蛋氨酸等重要物质的合成提供一碳单位来影响基因的甲基化和DNA的合成过程,与肿瘤的发生、发展关系密切。本研究旨在探讨河北省食管癌高发人群SHMT1C1420T单核苷酸多态性(singlenucleotidepolymorphism,SNP)与食管鳞状细胞癌(esophagealsquamouscellcarcinoma,ESCC)和贲门腺癌(gastriccardiacadenocarcinoma,GCA)易感性的关系。方法:采用双相引物-聚合酶链反应(polymerasechainreaction-withconfrontingtwo-pairprimers,PCR-CTPP)方法,检测584例ESCC患者、467例GCA患者和540名健康对照者的SHMT1C1420TSNP的基因型,并用非条件Logistic回归模型分析多态性与食管鳞癌和贲门腺癌发病风险的关系。结果:上消化道肿瘤(uppergastrointestinalcancers,UGIC)家族史可显著增加高发区人群食管鳞癌和贲门癌的发病风险,经性别、年龄、吸烟校正后的OR值分别为2.89(95%CI=2.23～3.73)和1.68(95%CI=1.28～2.23)。ESCC组和GCA组C/T基因型频率(分别为12.0%和10.9%)明显低于健康对照组(16.5%)(P值分别<0.05和0.01)。与C/C基因型相比,携带C/T基因型的个体ESCC、GCA的发病风险显著降低,经性别、年龄、吸烟、家族史校正后的OR值分别为0.70(95%CI=0.50～0.98)0.55(95%CI=0.38～0.81)。分层分析显示,与C/C基因型相比,C/T基因型可以显著降低非吸烟个体ESCC和GCA的发病风险,经性别、年龄、家族史校正后的OR值分别为0.54(95%CI=0.33～0.90),0.56(95%CI=0.33～0.95)。另外,虽然C/T基因型可显著降低UGIC家族史阳性和阴性个体贲门腺癌的发病风险[校正OR值分别为0.46(95%CI=0.24～0.90)和0.62(95%CI=0.38～0.99)],该基因型仅可降低UGIC家族史阳性个体ESCC的发病风险(校正OR值为0.51,95%CI=0.29～0.89)。结论:SHMT1C/T基因型可以显著降低中国河北省高发区ESCC、GCA的发病风险。更多还原

【Abstract】 BACKGROUND & OBJECTIVE: Serine hydroxymethyltransfe- rase (SHMT), a key enzyme in the folate metabolism, affects gene methylation and DNA synthesis through providing one-carbon units for purine, thymidylate, and methionine. It is closely related to the development and progression of tumors. This study was to investigate the correlations between SHMT1 C1420T single nucleotide polymorphisms (SNP) and susceptibilities to esophageal squamous cell carcinoma (ESCC) and gastric cardiac adenocarcinoma (GCA). METHODS: SHMT1 C1420T SNP was genotyped by polymerase chain reaction-confronting two-pair primers (PCR-CTPP) analysis in 584 ESCC patients, 467 GCA patients, and 540 healthy controls. The correlations between SHMT1 C1420T SNP polymorphisms and susceptibilities to ESCC and GCA were analyzed with Logistic regression model. RESULTS: Family history of upper gastrointestinal cancer (UGIC) significantly enhanced the risk of developing ESCC and GCA [the age, gender, smoking status, and family history of UGIC adjusted odds ratio (OR)=2.89, 95% confident interval (CI)=2.23-3.73; OR =1.68, 95% CI=1.28-2.23]. The frequency of 1420C/T genotype was significantly lower in ESCC and GCA patients than in healthy controls (12.0% vs. 16.5%, P<0.05; 10.9% vs. 16.5%, P<0.01). Compared with C/C genotype, C/T genotype significantly reduced susceptibilities to ESCC and GCA, with adjusted OR of 0.70 (95% CI=0.50-0.98) for ESCC and 0.55 (95% CI=0.38-0.81) for GCA. Stratification analysis showed that C/T genotype significantly reduced susceptibilities to ESCC and GCA among non-smokers, with adjusted OR of 0.54 (95% CI=0.33-0.90) for ESCC and 0.56 (95% CI=0.33-0.95) for GCA. In addition, C/T genotype significantly reduced susceptibility to GCA among individuals with or without UGIC history, with adjusted OR of 0.46 (95%CI=0.24-0.90) and 0.62 (95% CI=0.38-0.99) respectively, and reduced susceptibility to ESCC only among individuals with UGIC history, with adjusted OR of 0.51 (95% CI=0.29-0.89). CONCLUSION: SHMT1 1420C/T genotype could significantly reduce susceptibilities to ESCC and GCA among individuals from high risk areas in Hebei Province of China.更多还原