Rhodium(III)-catalyzed intermolecular [3+3] annulation of benzoxazines with quinone compounds: access to spiro-heterocyclic scaffolds.

A rhodium(III)-catalyzed redox-neutral spiroannulation approach to access the spiro[benzo[b][1,4]oxazine-benzo[c]chromene skeleton is described in this contribution. A variety of spiro[5.5]-heterocyclic scaffolds were obtained in moderate to excellent yields under mild conditions. Key features of this protocol are good substrate scope, silver-free conditions, low catalyst loadings, easy handling under air and 100% atom economy. Furthermore, scale-up reactions and late-stage derivatizations highlight the potential synthetic utility of this methodology.

Functional variants in the low-density lipoprotein receptor gene are associated with clear cell renal cell carcinoma susceptibility.

Recent studies indicate that abnormal levels of low-density lipoprotein (LDL), which is an important component of dyslipidaemia, are associated with alterations to cancer risk, including that of renal cell carcinoma (RCC). Single nucleotide polymorphisms at microRNA-binding sites contribute to cancer susceptibility and progression by affecting the messenger RNA (mRNA) function of target genes. In this case-control study, we examined the frequency of six potentially functional single nucleotide polymorphisms in the LDL receptor gene (LDLR) in 1004 clear cell RCC (ccRCC) patients and 1065 cancer-free subjects. Logistic regression analyses estimated odds ratios (ORs) and 95% confidence intervals (CIs). The association between genetic variants and levels of LDLR mRNA and protein was also evaluated. Compared with the CC genotype, multivariate logistic regression analysis showed that the LDLR rs2738464 variant GG genotype was associated with a significantly decreased ccRCC risk (P = 0.002, OR: 0.605, 95% CI: 0.439-0.833). Further functional experiments showed that the rs2738464 variant G allele affected miR-330 regulation of the LDLR 3'-untranslated region (UTR), increasing LDLR mRNA levels in patient kidney tissues. These findings suggest that LDLR rs2738464 may affect the affinity of miR-330 binding to the LDLR 3'-UTR, thus regulating LDLR expression and contributing to ccRCC risk.

MDM4 genetic variants and risk of gastric cancer in an Eastern Chinese population.

MDM4 is a p53-interacting protein and plays an important role in carcinogenesis. In this study of 1,077 gastric cancer (GCa) cases and 1,173 matched cancer-free controls, we investigated associations between three tagging single nucleotide polymorphisms (SNPs) (rs11801299 G>A, rs1380576 C>G and rs10900598 G>T) in MDM4 and gastric cancer risk in an Eastern Chinese Population. In logistic regression analysis, a significantly decreased GCa risk was associated with the rs1380576 GG variant genotype (adjusted odds ratio [OR] =0.74, 95% confidence interval [CI] =0.56-0.98) under a recessive model, which remained significant after correction by the false-positive reporting probability. This risk was more evident in subgroups of older subjects, males, never smokers, never drinkers and cancers of non-cardia. We then performed SNP-mRNA expression correlation analysis and found that the GG variant genotype was associated with significantly decreased expression of MDM4 mRNA in normal cell lines for 44 Chinese (P=0.032 for GG vs. CC) as well as for 269 multi-ethnic subjects (P<0.0001 for GG vs. CC). Our results suggest that the MDM4 rs1380576 G variant may be markers for GCa susceptibility. Larger, independent studies are warranted to validate our findings.

Is there a dose-dependent effect of genetic susceptibility loci for gastric cancer on prognosis of the patients?

Literature suggests that genetic variants associated with increased susceptibility to gastric cancer (GCa) are mostly located in genes involved in carcinogenesis and possibly tumor progression. Therefore, we hypothesize that high genetic susceptibility is also associated with prognosis of the patients. To test this hypothesis, we selected a total of 42 common genetic variants that were reportedly associated with GCa risk with a high level of evidence obtained from either genome-wide association studies (GWASs) or meta-analyses and performed survival analysis of patients used in a case-control analysis. We first used 1115 GCa cases and 1172 cancer-free controls of ethnic Han Chinese to construct a weighted genetic risk score (GRS). Then, we included 633 GCa cases with available clinical information, fit GRS in a fractional polynomial Cox proportional hazards regression model to investigate whether there is a dose-dependent effect of GRS on risk of death in survival analysis. Dynamic predictive value of genetic risk for prognosis was also calculated. The results showed that the increase of GRS had no effect on risk of death in these GCa patients. Compared with GCa patients with the medium GRS, there was no significant difference in survival in patients with either a low (P = 0.349) or a high (P = 0.847) GRS. The results unchanged when data were stratified by tumor stage and Lauren's classification. Time-dependent predictive value for prognosis in considering both clinical factors and GRS was comparable with that in considering clinical factors alone, for either all patients (P = 0.986) or stage- and Laruen type-based subgroups (P > 0.05 for all). In conclusion, higher polygenic susceptibility loci for GCa may not indicate worse prognosis of Chinese patients. Additional variants of relevant genes modulating GCa patients' survival need to be further identified.

Associations of genotypes and haplotypes of IL-17 with risk of gastric cancer in an eastern Chinese population.

Interleukin-17 plays a crucial role in inflammation-related carcinogenesis. We hypothesize that genetic variants in IL-17 are associated with gastric cancer (GCa) risk, and we genotyped five potentially functional single nucleotide polymorphisms (SNPs) (rs1974226 G > A, rs2275913 A > G, rs3819024 A > G, rs4711998 A > G, and rs8193036 C > T) of IL-17 in 1121 GCa patients and 1216 cancer-free controls in an eastern Chinese population. Logistic regression analysis was used to calculate odds ratios (OR) and 95% confidence intervals (CI). Meta-analysis and genotype-mRNA expression correlation were performed to further validate positive associations. We found that an increased GCa risk was independently associated with rs1974226 (adjusted OR = 2.60, 95% CI = 1.27-5.32 for AA vs. GG + GA) and rs2275913 (adjusted OR = 1.33, 95% CI = 1.03-1.72 for GA + AA vs. GG), while a decreased GCa risk was independently associated with rs3819024 (adjusted OR = 0.72, 95% CI = 0.54-0.96 for GG vs. AA + AG). Additional meta-analyses confirmed the observed risk association with rs2275913. We also found that two IL-17 haplotypes (G-G-G-A-C) and (A-G-G-A-C) (in the order of rs1974226, rs2275913, rs3819024, rs4711998 and rs8193036) were associated with a reduced GCa risk (adjusted OR = 0.64, 95% CI = 0.46-0.89 and adjusted OR = 0.38, 95% CI = 0.17-0.81, respectively). However, the expression Quantitative Trait Locus (eQTL) analysis for the genotype-phenotype correlation did not find mRNA expression changes associated with either the genotypes. In conclusions, genetic variants of IL-17 are likely to be associated with risk of GCa, and additional larger studies with functional validation are needed to explore the molecular mechanisms underlying the observed associations.

Associations of potentially functional variants in IL-6, JAKs and STAT3 with gastric cancer risk in an eastern Chinese population.

The interleukin-6 (IL-6)/JAK/STAT3 signaling pathway plays a central role in inflammation-mediated cancers, including gastric cancer (GCa). We evaluated associations between 10 potentially functional single nucleotide polymorphisms (SNPs) of four essential genes in the pathway and GCa risk in a study of 1,125 GCa cases and 1,221 cancer-free controls. We found that a significant higher GCa risk was associated with IL-6 rs2069837G variant genotypes [adjusted odds ratios (OR) = 1.33; 95% confidence interval (CI) = 1.12-1.59 for AG + GG vs. AA)] and JAK1 rs2230587A variant genotypes (adjusted OR = 1.20; 95% CI = 1.02-1.43 for GA + AA vs. GG). We also found that a significant decreased GCa risk was associated with STAT3 rs1053004G variant genotypes (adjusted OR = 0.84; 95% CI = 0.71-0.99 for AG + GG vs. AA). The combined analysis of IL-6 rs2069837G and JAK1 rs2230587A variant risk genotypes revealed that individuals with one-or-two risk genotypes exhibited an increased risk for GCa (adjusted OR = 1.34; 95% CI = 1.13-1.59). Genotypes and mRNA expression correlation analysis using the data from the HapMap 3 database provided further support for the observed risk associations. Larger studies are warranted to validate these findings.

PSCA polymorphisms and gastric cancer susceptibility in an eastern Chinese population.

The prostate stem cell antigen (PSCA) gene, which encodes a prostate-specific antigen (PSA), was identified as a gene involved in cell adhesion and proliferation. The associations between the PSCA rs2294008 and rs2976392 single nucleotide polymorphisms (SNPs) and gastric cancer (GCa) susceptibility were still controversial. To derive a more precise estimation of the associations, we conducted a case-control study of 1,124 cases and 1,192 controls in an eastern Chinese population. We found that the rs2294008T variant genotypes were associated with an increased GCa risk in this study population (CT vs CC, OR=1.59, 95% CI=1.33-1.89 and CT+TT vs CC, OR=1.38, 95% CI=1.17-1.62). For SNP rs2976392, the variant A genotypes were also associated with an increased GCa risk (AG vs GG, OR=1.61, 95% CI=1.35-1.91 and AG+AA vs GG, OR=1.47, 95% CI=1.25-1.74). The results were further validated by a meta-analysis. In conclusion, the results indicated that the PSCA rs2294008 T and rs2976392 A alleles were low-penetrate risk factors for GCa in this study population. However, large and well-designed studies are warranted to validate our findings.

Genetic variant rs4072037 of MUC1 and gastric cancer risk in an Eastern Chinese population.

Published data on the association between the MUC1 rs4072037A > G polymorphism and gastric cancer (GCa) risk were inconclusive. To derive a more precise estimation of the association, we conducted a large GCa study of 1,124 cases and 1,192 controls to confirm this association in an Eastern Chinese population. Our results showed that the G allele was strongly associated with a decreased GCa risk in the study population [GG vs. AA, odds ratio (OR) = 0.47, 95% confidence interval (CI) = 0.31-0.73; AG/GG vs. AA, OR = 0.82, 95% CI = 0.68-0.99; GG vs. AA/AG, OR = 0.48, 95% CI = 0.32-0.74]. These associations remained significant in subgroups of age, tumor site, drinking and smoking status. Moreover, this association was supported by an additional meta-analysis of published studies. In summary, these results suggest that the MUC1 rs4072037G allele may be a low-penetrating protection factor for GCa risk in Chinese populations.

A Functional Polymorphism (rs2494752) in the AKT1 Promoter Region and Gastric Adenocarcinoma Risk in an Eastern Chinese Population.

AKT is an important signal transduction protein that plays a crucial role in cancer development. Therefore, we evaluated associations between single nucleotide polymorphisms (SNPs) in the AKT promoter region and gastric cancer (GCa) risk in a case-control study of 1,110 GCa patients and 1,114 matched cancer-free controls. We genotyped five SNPs (AKT1 rs2494750G >C, AKT1 rs2494752A >G, AKT1 rs10138227C >T, AKT2 rs7254617G>A and AKT2 rs2304186G >T) located in the 5' upstream regulatory, first intron or promoter regions. In the logistic regression analysis, a significantly elevated GCa risk was associated with the rs2494752 AG/GG variant genotypes (adjusted odds ratio [OR] = 1.20, 95% confidence interval [CI] = 1.02-1.42) under a dominant genetic model, and this risk was more evident in subgroups of ever drinkers. The luciferase reporter assay showed that the rs2494752 G allele significantly increased luciferase activity. Our results suggest that the potentially functional AKT1 rs2494752 SNP may affect GCa susceptibility, likely by modulating the AKT1 promoter transcriptional activity. Larger, independent studies are warranted to validate our findings.

Genetic variant of PRKAA1 and gastric cancer risk in an eastern Chinese population.

Published data on the association between PRKAA1 rs13361707 T > C polymorphism and gastric cancer (GCa) susceptibility were inconclusive. To derive a more precise estimation of the association, we conducted a large-scale GCa study of 1,124 cases and 1,194 controls to confirm this association in an eastern Chinese population. Our results showed that the C allele of PRKAA1 rs13361707 increased the GC risk in the study population [CT vs. TT, odds ratio (OR) = 1.72, 95% confidence interval (CI) = 1.40-2.12; CC vs. TT, OR = 2.15, 95%CI = 1.70-2.71; CT/CC vs. TT, OR = 1.86, 95%CI = 1.53-2.26; CC vs.TT/CT, OR = 1.49, 95%CI = 1.24-1.79]. In addition, the association of C allele with an increased GCa risk was still significant in subgroups, when stratified by age, sex, tumor site, drinking and smoking status. Moreover, the findings in the present study were validated by our further meta-analysis. In summary, these results indicated that the C allele of PRKAA1 rs13361707 was a low-penetrate risk factor for GCa.

Genetic variations in the mTOR gene contribute toward gastric adenocarcinoma susceptibility in an Eastern Chinese population.

BACKGROUND AND AIM: Genetic variants in the mammalian target of rapamycin (mTOR) gene have become an interesting topic for the study of genetic susceptibility to cancer, but their associations with the risk of gastric cancer have not been fully investigated. MATERIALS AND METHODS: In a hospital-based case-control study of 1002 gastric cancer patients and 1003 cancer-free controls, we genotyped four potentially functional single nucleotide polymorphisms (SNPs) (rs1034528G>C, rs17036508T>C, rs3806317A>G, and rs2295080T>G) of mTOR and assessed their associations with the risk of gastric cancer using univariate and multivariate logistic regression analyses. We also used the multifactorial dimension reduction analysis to explore possible interactions and the false-positive report probabilities to assess significant findings. RESULTS: We found that rs1034528 CG/CC and rs3806317 GA/GG variant genotypes were associated with an increased risk of gastric cancer under a dominant model (adjusted odds ratio=1.27 and 1.22, respectively). In the combined analysis of all four SNPs under investigation, patients with 3-4 risk genotypes of mTOR had a significantly increased risk of gastric cancer (adjusted odds ratio=1.46, 95% confidence interval=1.19-1.79) compared with those with 0-2 risk genotypes. Stratified analysis indicated that this risk was more pronounced in subgroups of men, never-smokers, never-drinkers, and clinical stages III+IV. The multifactorial dimension reduction analysis suggested some evidence of interactions between the combined genotypes and other risk factors for gastric cancer. CONCLUSION: These findings suggest that potentially functional SNPs of mTOR may individually or collectively contribute to the risk of gastric cancer. Larger studies with diverse ethnic populations are warranted to validate our findings.

Potentially functional polymorphisms in the ERCC2 gene and risk of esophageal squamous cell carcinoma in Chinese populations.

ERCC2 is indispensable for nucleotide excision repair pathway, and its functional polymorphisms may be associated with cancer risk. In a large case-control study of 1126 esophageal squamous cell carcinomas (ESCC) patients and 1131 controls, we genotyped two SNPs in ERCC2 (rs238406 G > T and rs13181 T > G) and assessed their associations with ESCC risk. We found a significantly elevated ESCC risk associated with the rs238406 T variant genotypes (adjusted OR = 1.30 and 1.24, 95% CI = 1.02-1.66 and 1.03-1.49 for TG and TG/TT, respectively, compared with GG), particularly in the subgroup of those smoked more than 16 pack-years. Multivariate logistic regression analysis suggested a possible multiplicative gene-environment interaction between rs238406 genotypes and smoking (Pinteraction = 0.026) on ESCC risk. Although no significant risk associations were observed for rs13181, further mini meta-analysis with our and 18 other published studies of 5,012 cases and 8,238 controls found evidence of an association between the rs13181 variant G allele and esophageal cancer risk (TG/GG vs. TT, OR = 1.17; 95% CI = 1.02-1.33). Interestingly, we consistently found a significant correlation between variant genotypes of these two SNPs and ERCC2 mRNA expression. These findings suggest that potentially functional SNPs in ERCC2 may contribute to ESCC risk.

Genetic variations of the ADIPOQgene and risk of prostate cancer in Chinese Han men.

Adiponectin secreted by adipose tissue has been implicated in prostate carcinogenesis. Genetic variations in ADIPOQ are thought to influence the activity of adiponectin, thus relating to cancer occurrence. In this hospital-based case-control study of 917 prostate cancer (PCa) cases and 1036 cancer-free controls, we evaluated the association of single nucleotide polymorphisms in ADIPOQ with risk of PCa and adiponectin levels in Chinese Han men. Variants of ADIPOQ were genotyped by Taqman polymerase chain reaction method. The plasma adiponectin concentrations were measured by enzyme-linked immunosorbent assay (ELISA) in a subset of cases and controls. We found that the ADIPOQ rs3774262 variant AA genotype was associated with both decreased PCa risk [adjusted odds ratio (OR): 0.66, 95% confidence interval (CI) =0.48-0.92] and increased plasma adiponectin levels (P = 0.036 and 0.043), with significant difference by tumor grade, clinical stage, and aggressiveness. A significant interaction between ADIPOQ rs3774262 and body mass index was observed in modifying the risk of PCa (P = 6.7 × 10⁻³). ADIPOQ rs266729 and rs182052 were not related to PCa risk or plasma adiponectin levels. Our data support that ADIPOQ rs3774262 may affect PCa risk in combination with plasma adiponectin levels in Chinese Han men. It may contribute to the molecular basis for the association between obesity and PCa.

No association between TGFB1 polymorphisms and late radiotherapy toxicity: a meta-analysis.

BACKGROUND: Transforming growth factor-beta 1 (TGF-ß1) protein may be multifunctional and related to the development of fibrosis, induction of apoptosis, extracellular signaling and inhibition of proliferation in response to radiation-induced DNA damage. Several studies have investigated associations between single nucleotide polymorphisms (SNPs) in the TGFB1 gene and risk of late radiation-induced injury of normal tissue, but the conclusions remain controversial. METHODS: We searched three electronic databases (i.e., MEDLINE, EMBASE and EBSCO) for eligible publications and performed a meta-analysis assessing the association of three commonly studied SNPs in TGFB1 (i.e., rs1800469, rs1800470 and rs1800471) with risk of late radiation-induced injury of normal tissue. RESULTS: We finally included 28 case-only studies from 16 publications on aforementioned SNPs in TGFB1. However, we did not find statistical evidence of any significant association with overall risk of late radiotherapy toxicity in the pooled analysis or in further stratified analysis by cancer type, endpoint, ethnicity and sample size. CONCLUSIONS: This meta-analysis did not find statistical evidence for an association between SNPs in TGFB1 and risk of late radiation-induced injury of normal tissue, but this finding needs further confirmation by a single large study.

Association of LEP G2548A and LEPR Q223R polymorphisms with cancer susceptibility: evidence from a meta-analysis.

BACKGROUND: Numerous epidemiological studies have examined associations of genetic variations in LEP (G2548A, -2548 nucleotide upstream of the ATG start site) and LEPR (Q223R, nonsynonymous SNP in exon 6) with cancer susceptibility; however, the findings are inconsistent. Therefore, we performed a meta-analysis to comprehensively evaluate such associations. METHODS: We searched published literature from MEDLINE, EMBASE, Web of Science and CBM for eligible publications. We also assessed genotype-based mRNA expression data from HapMap for rs7799039 (G2548A) and rs1137101 (Q223R) in normal cell lines derived from 270 subjects with different ethnicities. RESULTS: The final analysis included 16 published studies of 6569 cases and 8405 controls for the LEP G2548A and 19 studies of 7504 cases and 9581 controls for the LEPR Q223R. Overall, LEP G2548A was statistically significantly associated with an increased risk of overall cancer (AA vs. GG: OR=1.27, 95% CI=1.05-1.54; recessive model: OR=1.19, 95% CI=1.00-1.41). Further stratifications by cancer type showed an increased risk for prostate cancer (recessive model: OR=1.26, 95% CI=1.05-1.51) but not for other cancers. For LEPR Q223R, no statistical evidence for an association with risk of cancer was found for all; however, further stratification by ethnicity showed an increased risk for Africans but not for other ethnicities. No significantly differences in LEP and LEPR mRNA expression were found among genotypes or by ethnicity. CONCLUSIONS: Despite some limitations, this meta-analysis found some statistical evidence for an association between the LEP 2548AA genotype and overall risk of cancer, particularly for prostate cancer, but given this variant did not have an effect on mRNA expression, this association warrants additional validation in large and well-designed studies.

Potentially functional polymorphisms in the CASP7 gene contribute to gastric adenocarcinoma susceptibility in an eastern Chinese population.

BACKGROUND: Caspase 7 (CASP7) is an important regulator and executioner in the apoptosis pathway and plays a crucial role in cancer development and progression. However, few studies have evaluated associations between functional single nucleotide polymorphisms (SNPs) in the 3' untranslational region (UTR) of CASP7 and risk of gastric cancer. METHODS: In a case-control study of 1117 patients with gastric cancer and 1146 cancer-free controls with frequency matching on age and sex, we genotyped four potentially functional SNPs (rs4353229T>C, rs10787498T>G, rs1127687G>A and rs12247479G>A) located in the microRNA binding sites of the CASP7 3' UTR by using Taqman assays and evaluated their associations with risk of gastric cancer by using logistic regression analyses as well as multifactorial dimension reduction (MDR) analysis. RESULTS: In the single-locus analysis, only the CASP7 rs4353229 TT genotype was associated with 0.83-fold decreased risk (95% confidence interval [CI] = 0.70-0.98) of gastric cancer under a recessive model, compared with the CT/CC genotypes. In the combined analysis of all four SNPs, we found that the risk of gastric cancer decreased by 19% in those carrying any of the risk genotypes (adjusted odds ratio = 0.81, 95% CI = 0.68-0.96), compared with those carrying zero risk genotypes, and this risk was more evident in subgroups of younger age (<59 years), females, non-smokers, non-drinkers and patients with non-gastric cardia adenocarcinoma. Further MDR analysis suggested some evidence of interactions between the combined genotypes and other risk factors for gastric cancer. CONCLUSIONS: Potentially functional CASP7 variants may contribute to risk of gastric cancer. Larger studies with different ethnic populations are warranted to validate our findings.

ERCC1 and ERCC2 variants predict survival in gastric cancer patients.

PURPOSE: ERCC1 and ERCC2 play critical roles in the nucleotide excision repair pathway that effectively repairs DNA damage induced by chemotherapeutic agents. Therefore, functional single nucleotide polymorphisms (SNPs) in these genes could have an impact on clinical outcomes in cancer patients who received chemotherapy. However, few studies have simultaneously investigated the roles of ERCC1 and ERCC2 SNPs in clinical outcomes in gastric cancer patients. EXPERIMENTAL DESIGN: We genotyped by the TaqMan assay three common, potentially functional ERCC1 (rs3212986) and ERCC2 SNPs (rs13181 and rs1799793) in 360 gastric cancer patients. We used both Kaplan-Meier tests and Cox proportional hazards models to evaluate the effects of ERCC1 and ERCC2 genotypes and haplotypes on clinical outcomes. RESULTS: We found that, compared with ERCC2 rs1799793 GG+AG genotypes, the homozygous variant AA genotype was associated with significantly poorer overall survival (OS) (AA vs. GG+AG, log-rank P=0.012) and significantly higher risk of death (AA vs. GG+AG, Adjusted hazards ratio [HR] 2.13; 95% CI, 1.28 to 3.56; P=0.004). In combined analyses, patients with any one of the three unfavorable genotypes (i.e. ERCC1 rs3212986 TT, ERCC2 rs13181 GG and rs1799793 AA) had statistically significant hazards of poor prognosis (Adjusted HR, 1.54; 95% CI, 1.06 to 2.25; P=0.025), compared with those without any unfavorable genotypes. Furthermore, the haplotype A-G-G (rs1799793/rs13181/rs3212986) had a significant impact on OS (Adjusted HR, 1.57; 95% CI, 1.11 to 2.21; P=0.011), compared with the common haplotype G-T-G. CONCLUSION: ERCC1 and ERCC2 functional SNPs may jointly affect OS in Caucasian gastric cancer patients. Additional large prospective studies are essential to confirm our findings.

Polymorphisms in mTORC1 genes modulate risk of esophageal squamous cell carcinoma in eastern Chinese populations.

INTRODUCTION: Mammalian target of rapamycin complex 1 (mTORC1) is an evolutionary conserved multiprotein complex that functions as a key regulator of gene transcription, protein translation, and autophagy. No studies have assessed associations between functional single nucleotide polymorphisms (SNPs) in mTORC1 genes and risk of esophageal squamous cell carcinoma (ESCC). METHODS: : In a case-control study of 1126 ESCC patients and 1131 cancer-free controls, we genotyped eight SNPs in mTORC1 (mTOR rs1883965 G>A and rs2536 T>C, mLST8 rs3160 C>T and rs26865 G>A, RPTOR rs3751934 C>A, rs1062935 T>C, rs3751932 T>C and rs12602885 G>A) and assessed their associations with risk of ESCC. RESULTS: In the single-locus analyses, we found a significantly altered risk of ESCC associated with mTOR rs1883965 A variant genotypes (adjusted OR = 1.27 and 1.26; 95% confidence interval = 1.01-1.60 and 1.01-1.58 for GA and GA/AA, respectively, compared with GG) but not with other SNPs. In the combined analysis of the eight SNPs, we found individuals with two or more unfavorable genotypes exhibited an increased risk for ESCC (adjusted OR = 1.35; 95% confidence interval = 1.20-1.62), compared with those with less than two unfavorable genotypes. Such a cumulative effect was dose-dependent (ptrend = 0.004). In the multiple dimension reduction analysis, mTOR rs1883965 was consistently suggested as the strongest individual factor for ESCC risk, and the model including all SNPs yielded the lowest prediction error of 17.66% for model validation. CONCLUSIONS: These findings suggest that functional SNPs of mTORC1 genes may individually or collectively contribute to ESCC risk. Further validation of these findings is warranted.

Associations of Lys939Gln and Ala499Val polymorphisms of the XPC gene with cancer susceptibility: a meta-analysis.

XPC polymorphisms may alter DNA repair capacity, thus leading to genetic instability and carcinogenesis. Numerous studies have investigated the associations of XPC Lys939Gln (rs2228001) and Ala499Val (rs2228000) polymorphisms with cancer susceptibility; however, the findings are inconclusive. We searched literature from MEDLINE and EMBASE for eligible publications that assessed the associations between these two polymorphisms and cancer risk. We also assessed genotype-mRNA expression correlation data from HapMap for rs2228001 and rs2228000 in normal cell lines derived from 270 subjects with different ethnicities. The final analysis included 62 published studies of 25,708 cases and 30,432 controls for the Lys939Gln and 34 studies with 14,877 cases and 17,888 controls for the Ala499Val. Overall, Lys939Gln was significantly associated with an increased overall cancer risk (Gln/Gln vs. Lys/Lys: OR = 1.16, 95% CI = 1.07 - 1.25, p < 0.001; recessive model: OR = 1.14, 95% CI = 1.06 - 1.22, p < 0.001; dominant model: OR = 1.06, 95% CI = 1.01 - 1.11, p = 0.015 and Gln vs. Lys: OR = 1.07, 95% CI = 1.03 - 1.10, p < 0.001) and further stratifications showed an increased risk for bladder, lung and colorectal cancer, Asian populations and population-based studies. Likewise, Ala499Val was also significantly associated with an increased overall cancer risk (Val/Val vs. Ala/Ala: OR = 1.21, 95% CI = 1.07 - 1.36, p = 0.003 and recessive model: OR = 1.20, 95% CI = 1.08 - 1.34, p = 0.001) and further stratification showed an increased risk for breast and bladder cancer, particularly in Asian populations. Interestingly, significantly correlation between XPC genotypes and mRNA expression was found only for Asian populations as well. Despite some limitations, this meta-analysis established some solid statistical evidence for an association between XPC polymorphisms and cancer risk, which warrants further validation in single large studies.

Genetic variations of mTORC1 genes and risk of gastric cancer in an Eastern Chinese population.

Mammalian target of rapamycin complex 1 (mTORC1) plays an important role in maintaining proper cellular functions, and genetic variations in this complex may affect cancer risk. In this study, we examined the associations between eight potential functional single nucleotide polymorphisms in the mTORC1 genes (rs2536T>C and rs1883965G>A for mTOR, rs3160T>C, and rs26865A>G for mLST8, rs3751934C>A, rs1062935T>C, rs3751932T>C, and rs12602885G>A for Raptor, not included in published gastric cancer genome-wide association studies) and gastric cancer risk in 1125 gastric cancer cases and 1196 cancer-free controls. We performed conditional logistic regression and multifactor dimensionality reduction (MDR) analyses to assess their associations with gastric cancer risk. We also used false-positive report probabilities (FPRP) for assessing significant findings. We found that only the rs1883965A variant genotypes were associated with an increased risk of gastric cancer (AG vs. GG: adjusted odds ratio (OR) = 1.26, 95% confidence interval (CI) = 1.00-1.59; AA vs. GG: adjusted OR = 1.85, 95% CI = 0.67-5.16 and dominant model: adjusted OR = 1.28, 95% CI = 1.03-1.61). Patients with ≥1 risk genotypes of mTOR had significant increased risk (adjusted OR = 1.25, 95% CI = 1.04-1.49), compared with those having zero risk genotypes. In the stratified analysis, the risk effect of the rs1883965 AG/AA genotypes was evident in subgroups of ever-smokers, non-gastric cardia adenocarcinoma and clinical stage I + II, which were noteworthy findings as evaluated by FPRP. The MDR analysis identified smoking status and rs1883965 as the strongest two-factors for gastric cancer risk. These data support the hypothesis that functional polymorphisms of mTOR may contribute to gastric cancer risk. Clearly, our results require validation in larger studies with different ethnic populations.