Characterization of a canine tetranucleotide microsatellite marker located in the first intron of the tumor necrosis factor alpha gene

Association between TNF-ɑ-308G/A polymorphism and esophageal cancer risk: An updated meta-analysis and trial sequential analysis

Background: TNF-α-308G/A (rs1800629) polymorphism has been previously implicated in the susceptibility to esophageal cancer, but results of these studies remained controversial or ambiguous. A meta-analysis was conducted to provide a more reliable conclusion about the association between TNF-ɑ-308G/A polymorphism and risk of esophageal cancer.

Methods: Databases such as PubMed, EMBASE, Web of Science and CNKI were searched for relevant articles published till June 1, 2018. We used the pooled odds ratios (ORs) with 95% confidence intervals (CIs) to evaluate the strength of such associations. Subgroup analysis was carried out according to ethnicity, source of controls and genotyping method. A trial sequential analysis (TSA) was performed to reduce the risk of type I error and evaluate whether the results of our meta-analysis were credible.

Results: A total of 9 published case-control studies with 1,435 esophageal cancer patients and 3,762 healthy controls were identified. Overall, our results indicated no significant correlation between TNF-α-308G/A polymorphism and increased risk of esophageal cancer in the fixed-effects model (allele model: pooled OR=1.11, 95% CI: 0.96-1.27, homozygote model: pooled OR=1.23, 95% CI: 0.77-1.95, heterozygote model: pooled OR=1.14, 95% CI: 0.97-1.35, dominant model: pooled OR=1.14, 95% CI: 0.97-1.34 and recessive model: pooled OR=1.00, 95% CI: 0.64-1.56). Subgroup analysis by ethnicity, source of controls and genotyping method showed no significant increase in the risk of esophageal cancer. TSA results need further investigation with a large sample size to certify such association.

Conclusions: This meta-analysis study suggested no significant association between TNF-ɑ-308G/A polymorphism and the risk of esophageal cancer.

Sequence analysis of three canine adipokine genes revealed an association between TNF polymorphisms and obesity in Labrador dogs

Obesity is an emerging health problem in purebred dogs. Due to their crucial role in energy homeostasis control, genes encoding adipokines are considered candidate genes, and their variants may be associated with predisposition to obesity. Searching for polymorphism was carried out in three adipokine genes (TNF, RETN and IL6). The study was performed on 260 dogs, including lean (n = 109), overweight (n = 88) and obese (n = 63) dogs. The largest cohort was represented by Labrador Retrievers (n = 136). Altogether, 24 novel polymorphisms were identified: 12 in TNF (including one missense SNP), eight in RETN (including one missense SNP) and four in IL6. Distributions of five common SNPs (two in TNF, two in RETN and one in IL6) were further analyzed with regard to body condition score. Two SNPs in the non-coding parts of TNF (c.-40A>C and c.233+14G>A) were associated with obesity in Labrador dogs. The obtained results showed that the studied adipokine genes are highly polymorphic and two polymorphisms in the TNF gene may be considered as markers predisposing Labrador dogs to obesity.