BackgroundAs an imperative part of PI3K/Akt/mTOR pathway, mammalian target of rapamycin (mTOR) has been demonstrated to increase in gastric cancer cells and tumors. Our research explored the relationship between single nucleotide polymorphism (SNP) rs2295080 in mTOR promoter region and the risk of gastric cancer (GC).MethodsSeven hundred and fifty-three (753) gastric adenocarcinoma patients and 854 matched healthy subjects were recruited in the cancer association study and 60 tissues were used to test the expression of mTOR. Unconditional logistic regression was selected to evaluate the association between the rs2295080 T>G polymorphism and GC risk. We then examined the functionality of this promoter genetic variant by luciferase assay and EMSA.ResultsIndividuals with G allele had a 23% decreased risk of GC, comparing with those carrying T allele (adjusted OR = 0.77, 95% CI = 0.65–0.92). This protective effect of G allele stood out better in male group. Meanwhile, GC patients carrying TG/GG genotype also displayed a decreased mRNA level of mTOR (P = 0.004). In luciferase assay, T allele tended to enhance the transcriptional activity of mTOR with an approximate 0.5-fold over G allele. Furthermore, EMSA tests explained that different alleles of rs2295080 displayed different affinities to some transcriptional factor.ConclusionThe mTOR promoter polymorphism rs2295080 was significantly associated with GC risk. This SNP, which effectively influenced the expression of mTOR, may be a new biomarker of early diagnosis of gastric cancer and a suitable indicator of utilizing mTOR inhibitor for treatment of GC.

Human telomerase reverse transcriptase (TERT) is essential for the maintenance of telomere DNA length, chromosomal stability and cellular immortality. We hypothesized that TERT polymorphisms are associated with risk of childhood acute lymphoblastic leukemia (ALL). We first conducted a case-control study of 570 ALL cases and 673 cancer-free controls of Chinese children, using the tagging single-nucleotide polymorphisms (tSNPs) approach. We then examined the functionality of the important SNPs. We found that TERT promoter region tSNP (rs2735940) and two intron region tSNPs (rs2736100 and rs10069690) were associated with risk of childhood ALL (P = 0.036, 0.011 and 0.022, respectively, in allele comparison). The in vitro luciferase assays in Jurkat cells showed an increased transcriptional activity of rs2735940 T allele compared with the C allele. Additional experiments with ALL bone marrow revealed that the rs2735940 T allele increased levels of the TERT messenger RNA. Notably, TERT intron 2 polymorphism (rs2736100) was associated with lower telomerase activity and longer telomeres. Our findings suggested that TERT promoter rs2735940 polymorphism may affect the TERT activity, and rs2736100 may be associated with telomere function, and thus, it is a potential biomarker for genetic susceptibility to ALL in Chinese children.

Our previous genome-wide miRNA microarray study revealed that miR-107 was upregulated in gastric cancer (GC). In this study we aimed to explore its biological role in the pathogenesis of GC. Integrating in silico prediction algorithms with western blotting assays revealed that miR-107 inhibition enhanced NF1 (neurofibromin 1) mRNA and protein levels, suggesting that NF1 is one of miR-107 targets in GC. Luciferase reporter assay revealed that miR-107 suppressed NF1 expression by binding to the first potential binding site within the 3′-UTR of NF1 mRNA. mRNA stable assay indicated this binding could result in NF1 mRNA instability, which might contribute to its abnormal protein expression. Functional analyses such as cell growth, transwell migration and invasion assays were used to investigate the role of interaction between miR-107 and its target on GC development and progression. Moreover, We investigated the association between the clinical phenotype and the status of miR-107 expression in 55 GC tissues, and found the high expression contributed to the tumor size and depth of invasion. The results exhibited that down regulation of miR-107 opposed cell growth, migration, and invasion, whereas NF1 repression promoted these phenotypes. Our findings provide a mechanism by which miR-107 regulates NF1 in GC, as well as highlight the importance of interaction between miR-107 and NF1 in GC development and progression.

Genetic variations in miRNAs have been demonstrated to be capable of altering miRNA expression, consequently affecting many cancer-related biological processes. The MIR196A2 rs11614913 (T > C) polymorphism has been reported to be associated with various cancers development and progression. In our study, we aim to explore whether this polymorphism is relevant to the genetic susceptibility and prognosis of gastric cancer in a Chinese population. We analyzed the correlations of rs11614913 polymorphism with gastric cancer susceptibility in test and validation sets. The test set comprised 749 cases and 900 controls, while the validation set enrolled 940 cases and 1046 controls. Moreover, we evaluated the association between the polymorphism and gastric cancer prognosis in the validation set with follow-up information. The variant rs11614913 CC genotype was associated with a significantly reduced risk of gastric cancer in both sets (adjusted odds ratio [OR] = 0.78, 95% confidence interval [CI] = 0.62-0.99 for the test set and 0.64, 0.52-0.80 for the validation set) compared with the CT/TT genotypes. Furthermore, the CC genotype was associated with a significantly increased survival of gastric cancer compared with the CT/TT genotypes (adjusted hazard ratio [HR] = 0.72, 95% CI = 0.55-0.95), and the association was more prominent among patients with non-cardia gastric cancer than those with cardia gastric cancer (adjusted HR = 0.57, 95% CI = 0.40-0.83 for NCGC and 1.00, 0.65-1.53 for CGC). Our results suggested that the genetic variation of MIR196A2 may play a role in gastric cancer tumorigenesis.

These findings supported miR-26a and miR-148a could serve as potential prognostic biomarkers for GC.