Susi Manoela Dias, Lourenço Caroline de Matos, Rasmussen Lucas Trevizani, Payão Spencer Luis Marques, Rossi Ana Flávia Teixeira, Silva Ana Elizabete, de Oliveira-Cucolo Juliana Garcia
Department of Graduate-Level Research, USC-Sacred Heart University, Bauru 17011-970, SP, Brazil.
Department of Genetics and Molecular Biology, FAMEMA-Marilia Medical School, Marília 17519-030, SP, Brazil.
World J Gastrointest Oncol. 2019 Nov 15;11(11):998-1010. doi: 10.4251/wjgo.v11.i11.998.
Toll-like receptors (TLRs) are the first line of host defense, and are involved in () recognition and activation of both inflammatory and carcinogenic processes. The presence of single nucleotide polymorphisms (SNPs) in genes that activate the immune response may modulate the risk of precancerous lesions and gastric cancer (GC). Among them, Toll-like receptor 9 (TLR9) polymorphisms have emerged with a risk factor of infectious diseases and cancer, however the studies are still inconclusive.
To evaluate whether TLR9 rs5743836 and rs187084 SNPs contribute to the risk of gastric carcinogenesis, and its influence on mRNA expression.
A case-control study was conducted to evaluate two TLR9 SNPs (TLR91237 TC-rs5743836 and TLR91486 CT-rs187084) in chronic gastritis (CG) and GC patients. A total of 609 DNA samples of peripheral blood [248 CG, 161 GC, and 200 samples from healthy individuals (C)] were genotyped by polymerase chain reaction-restriction fragment length polymorphism. All samples were tested for the infection using Hpx1 and Hpx2 primers. Quantitative polymerase chain reaction by TaqMan assay was used to quantify TLR9 mRNA from fresh gastric tissues (48 GC, 26 CG, and 14 C).
For TLR91237, the TC + CC or CC genotypes were associated with a higher risk of GC than C [recessive model odds ratio (OR) = 5.01, 95% confidence interval (CI): 2.52-9.94, < 0.0001], and the CG (recessive model OR =4.63; 95%CI: 2.44-8.79, < 0.0001) groups. For TLR9-1486, an association between the CT + TT genotypes and increased risk of both GC (dominant model OR = 2.72, 95%CI: 1.57-4.72, < 0.0001) and CG (dominant model OR = 1.79, 95%CI: 1.15-2.79, = 0.0094) was observed when compared to the C group. Moreover, the presence of TLR9-1237 TC/CC + TLR9-1486 CC genotypes potentiate the risk for this neoplasm (OR = 18.57; 95%CI: 5.06-68.15, < 0.0001). The TLR9 mRNA level was significantly higher in the GC group (RQ = 9.24, < 0.0001) in relation to the CG group (RQ = 1.55, = 0.0010) and normal mucosa (RQ = 1.0). When the samples were grouped according to the polymorphic genotypes and the presence of infection, an influence of TLR9-1237 TC + CC polymorphic genotypes ( = 0.0083) and infection ( < 0.0001) was observed on the upregulation of mRNA expression.
Our findings show that TLR9 rs5743836 and rs187084 polymorphisms are associated with a higher risk of carcinogenesis gastric, and that TLR9 mRNA levels can be modulated by TLR9-1237 TC + CC variant genotypes and infection.
Toll样受体（TLRs）是宿主防御的第一道防线，参与炎症和致癌过程的识别与激活。激活免疫反应的基因中存在单核苷酸多态性（SNPs）可能会调节癌前病变和胃癌（GC）的风险。其中，Toll样受体9（TLR9）多态性已成为传染病和癌症的一个风险因素，但研究结果仍无定论。
评估TLR9 rs5743836和rs187084单核苷酸多态性是否会增加胃癌发生风险及其对mRNA表达的影响。
进行一项病例对照研究，以评估慢性胃炎（CG）和GC患者中的两个TLR9单核苷酸多态性（TLR91237 TC-rs5743836和TLR91486 CT-rs187084）。通过聚合酶链反应-限制性片段长度多态性对总共609份外周血DNA样本[248例CG、161例GC和200例健康个体（C）的样本]进行基因分型。使用Hpx1和Hpx2引物对所有样本进行幽门螺杆菌感染检测。采用TaqMan法进行定量聚合酶链反应，以定量新鲜胃组织（48例GC、26例CG和14例C）中的TLR9 mRNA。
对于TLR91237，与C组相比，TC + CC或CC基因型与GC风险较高相关[隐性模型优势比（OR）= 5.01，95%置信区间（CI）：2.52 - 9.94，P < 0.0001]，与CG组（隐性模型OR = 4.63；95%CI：2.44 - 8.79，P < 0.0001）相比也是如此。对于TLR9 - 1486，与C组相比，观察到CT + TT基因型与GC（显性模型OR = 2.72，95%CI：1.57 - 4.72，P < 0.0001）和CG（显性模型OR = 1.79，95%CI：1.15 - 2.79，P = 0.0094）风险增加相关。此外，TLR9 - 1237 TC/CC + TLR9 - 1486 CC基因型的存在会增加这种肿瘤的风险（OR = 18.57；95%CI：5.06 - 68.15，P < 0.0001）。与CG组（RQ = 1.55，P = 0.0010）和正常黏膜（RQ = 1.0）相比，GC组的TLR9 mRNA水平显著更高（RQ = 9.24，P < 0.0001）。当根据多态基因型和幽门螺杆菌感染情况对样本进行分组时，观察到TLR9 - 1237 TC + CC多态基因型（P = 0.0083）和幽门螺杆菌感染（P < 0.0001）对mRNA表达上调有影响。
我们的研究结果表明，TLR9 rs5743836和rs187084多态性与胃癌发生风险较高相关，并且TLR9 mRNA水平可受TLR9 - 1237 TC + CC变异基因型和幽门螺杆菌感染的调节。
