Association of genetic polymorphisms of MK, IL-4, p16, p21, p53 genes and human gastric cancer in Taiwan

Role of Interleukins and New Perspectives in Mechanisms of Resistance to Chemotherapy in Gastric Cancer

Gastric cancer (GC) is the fourth most common cancer in the world in terms of incidence and second in terms of mortality. Chemotherapy is the main treatment for GC. The greatest challenge and major cause of GC treatment failure is resistance to chemotherapy. As such, research is ongoing into molecular evaluation, investigating mechanisms, and screening therapeutic targets. Several mechanisms related to both the tumor cells and the tumor microenvironment (TME) are involved in resistance to chemotherapy. TME promotes the secretion of various inflammatory cytokines. Recent studies have revealed that inflammatory cytokines affect not only tumor growth, but also chemoresistance. Cytokines in TME can be detected in blood circulation and TME cells. Inflammatory cytokines could serve as potential biomarkers in the assessment of chemoresistance and influence the management of therapeutics in GC. This review presents recent data concerning research on inflammatory cytokines involved in the mechanisms of chemoresistance and provides new clues in GC treatment.

Possible Roles of Interleukin-4 and -13 and Their Receptors in Gastric and Colon Cancer

Interleukin (IL)-4 and -13 are structurally and functionally related cytokines sharing common receptor subunits. They regulate immune responses and, moreover, are involved in the pathogenesis of a variety of human neoplasms. Three different receptors have been described for IL-4, but only IL-4 receptor type II (IL-4Rα/IL-13Rα1) is expressed in solid tumors. While IL-13 can also bind to three different receptors, IL-13 receptor type I (IL-4Rα/IL-13Rα1/IL-13Rα2) and type II (IL-4Rα/IL-13Rα1) are expressed in solid tumors. After receptor binding, IL-4 and IL-13 can mediate tumor cell proliferation, survival, and metastasis in gastric or colon cancer. This review summarizes the results about the role of IL-4/IL-13 and their receptors in gastric and colon cancer.

Association of Midkine and Pleiotrophin Gene Polymorphisms With Systemic Lupus Erythematosus Susceptibility in Chinese Han Population

In a previous study, we have reported an increased plasma midkine (MK) and pleiotrophin (PTN) concentrations in patients with systemic lupus erythematosus (SLE) and the increase in MK and PTN associated with inflammatory cytokines interleukin (IL)-17 level and some clinical manifestations, suggesting the underlying association of MK and PTN with SLE. This study was conducted to investigate the association between common single-nucleotide polymorphisms (SNPs) in the MK and PTN gene and SLE susceptibility. A total of 989 subjects (496 SLE patients and 493 healthy controls) were included and genotyped for three MK SNPs and seven PTN SNPs in using improved multiple ligase detection reaction (iMLDR). Results have demonstrated no significant differences for genotype and allele frequencies in all 10 SNPs between SLE patients and healthy controls. Case-only analysis in SLE revealed that, in MK gene, the genotype frequency of AA/AG (rs35324223) was significantly lower in patients with photosensitivity than those without; the allele frequency of A/G (rs20542) was significantly higher in patients without serositis. In PTN gene, the A/G allele frequency (rs322236), C/T allele frequency, and TT/CT genotype frequency (rs6970141) showed significantly increased results in patients with immunological disorder compared to those without. Furthermore, no significant differences in plasma MK and PTN concentrations with its SNPs genotypes were found. MK and PTN SNPs showed no associations with SLE genetic susceptibility, but it may be associated with the course of this disease; further studies are needed to focus on the mechanism of MK and PTN genes in the pathogenesis of SLE.

Effects of IL-4-590C/T (rs2243250) Polymorphism on the Susceptibility of Smoking-Related Cancer: A Meta-Analysis Involving 11,407 Subjects

Background

Several previous studies have assessed the relationship between IL-4-590C/T gene polymorphism and smoking-related cancer in recent years; however, the results remain controversial. Based on it, the study intends to clarify whether IL-4-590C/T variant increases the risk of smoking-related cancer through meta-analysis.

Methods

We searched PubMed, EMBASE, Web of Science, Cochrane Library database, China National Knowledge Infrastructure, and Wanfang data information service platform to collect qualified case-control studies in strict accordance with the inclusion and exclusion standards. The 95% confidence interval (95% CI) and its odds ratio (OR) were adopted to access the relation between IL-4-590C/T gene polymorphism and smoking-related cancer; sensitivity analysis and publication bias assessment were carried out after the studies' quality evaluation.

Results

17 studies were included in total, with 5,061 patients and 6,346 control cases. A significant association between IL-4-590C/T variant and smoking-related cancer in total population was revealed in our meta-analysis results, and IL-4-590C/T variant might have a relatively protective effect on smoking-related cancer (CT vs. TT: P=0.026, OR = 0.900, 95% CI: 0.820–0.987). Subgroup analysis by ethnicity showed that the IL-4-590C/T polymorphism was associated with a decreased risk of smoking-related cancer in the Asian population (CT vs. TT: P=0.008, OR = 0.878, 95% CI: 0.798–0.967; CC + CT vs. TT: P=0.030, OR = 0.903, 95% CI: 0.824–0.990). Subgroup analysis based on types of cancer demonstrated the IL-4-590C/T variant achieved a lower risk in renal cell cancer (CC vs. TT: P=0.046, OR = 0.640, 95% CI: 0.412–0.993).

Conclusion

There is a conspicuous association between IL-4-590C/T polymorphism and decreased risk of smoking-related cancer, particularly in Asians. And IL-4-590C/T polymorphism may have a protective effect on renal cell cancer.

Associations of common IL-4 gene polymorphisms with cancer risk: A meta-analysis

Cancer incidence is dramatically increasing worldwide, therefore improved prediction and therapeutic methods are needed. Single nucleotide polymorphisms in cytokine genes may contribute to carcinogenesis. Interleukin (IL)-4 gene polymorphisms have been intensively studied with regard to their associations with cancer. However, the results of these previous studies remain inconclusive. The present study, therefore, aimed to conduct a meta-analysis of previously published studies in order to clarify the association of IL-4 with cancer risk. Eligible published articles were searched in Medline, PubMed, Embase and China National Knowledge Infrastructure databases up to March 2016. Odds ratios and 95% confidence intervals were used to identify potential associations between IL-4 genetic polymorphisms and the risk of cancer. A meta-analysis was then performed on 10,873 patients and 14,328 controls for IL-4 rs2243250 polymorphism, 3,970 patients and 5,686 controls for IL-4 rs2070874 polymorphism, and 1,896 patients and 2,526 controls for IL-4 rs79071878 polymorphism. A significant association with cancer risk was observed for rs2243250 and rs79071878 polymorphisms. In the subgroup analysis by cancer type, rs2243250 polymorphism was demonstrated to be associated with an increased risk of gastric cancer and breast cancer, rs2070874 polymorphism was correlated with leukemia and oral carcinoma, and rs79071878 polymorphism was relevant to bladder carcinoma risk. In the subgroup analysis by ethnicity, IL-4 rs2243250 polymorphism was demonstrated to be associated with cancer risk in both Caucasian and Asian populations, rs2070874 was associated with cancer risk in Asian populations, while rs79071878 polymorphism was associated with cancer risk in Caucasian populations. In conclusion, the present results suggested that the IL-4 rs2243250 and rs79071878 polymorphisms were associated with cancer susceptibility. Further subgroup analyses revealed that the effects of IL-4 gene polymorphisms on cancer risk may vary by cancer type and by ethnicity.

Association of IL4, IL13, and IL4R polymorphisms with gastrointestinal cancer risk: A meta-analysis

Background

Previous studies have suggested that IL4, IL13, and IL4R are associated with serum IgE levels and allergies, and common variants of these genes may alter cancer risk. To clarify these associations, we conducted a meta-analysis to investigate the associations of IL4, IL13, and IL4R polymorphisms with gastrointestinal cancer risk.

Methods

We used 27 eligible case–control studies describing the associations of six polymorphisms of IL4, IL13, and IL4R with gastrointestinal cancer risk to calculate summary odds ratios (ORs) and 95% confidence intervals (CIs) using five different genetic models. The Q-statistic and I² statistic were calculated to examine heterogeneity.

Results

The IL4 rs2070874 T allele seems to be associated with an increased risk of gastrointestinal cancer (OR 1.11; 95% CI, 1.00–1.24 for T allele vs. C allele). This association was significant in studies conducted outside of Asia (OR 1.28; 95% CI, 1.03–1.58 for T allele vs. C allele) and in studies investigating the association with gastric cancer (OR 1.17; 95% CI, 1.03–1.34 for T allele vs. C allele). However, the IL4R rs1801275 heterozygote seems to be associated with a reduced risk of gastrointestinal cancer (OR 0.79; 95% CI, 0.65–0.96 for AG vs. AA). Other polymorphisms did not show any significant associations with gastrointestinal cancer risk in any of the genetic models and subgroup analyses.

Conclusions

Our results suggest that certain polymorphisms of IL4 and IL4R may affect susceptibility to gastrointestinal cancer. However, further studies are required to confirm these findings.

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This meta-analysis included 27 eligible case–control studies.

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IL4 rs2070874 T allele may increase the risk of gastrointestinal cancer.

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IL4R rs1801275 variant may reduce the risk of gastrointestinal cancer.

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Polymorphisms in IL4 and IL4R may affect susceptibility to gastrointestinal cancer.

Interleukin (IL)-4 -590C>T polymorphism is not associated with the susceptibility of gastric cancer: An updated meta-analysis

Gastric cancer (GC) is a common cancer affecting patients around the world. The pathogenesis of gastric cancer has not been understood completely. Genetic mutations and the inflammation induced by Helicobacter pylori (HP) seem to play important roles. The cytokine Interleukin-4 (IL-4) has effects in inflammation, allergies and cancer including GC. The association of IL-4 -590 C>T polymorphism and gastric cancer has been studied in different populations with inconsistent results. Here, we report this meta-analysis showing that the polymorphism of IL-4 -590C>T might not be associated with the GC susceptibility in both Asian and Caucasian populations.

Genetic association between interluekin-4 rs2243250 polymorphism and gastric cancer susceptibility: evidence based on a meta-analysis

Purpose

Numerous studies have suggested that the interleukin-4 (IL-4) rs2243250 polymorphism is associated with gastric cancer susceptibility. However, the results were inconsistent. Hence, we carried out a meta-analysis to confirm the conclusion.

Methods

We searched PubMed, Embase, CBM, CNKI, and Wanfang Data to identify relevant studies up to August 20, 2015. Odds ratio (OR) and 95% confidence interval (CI) were used to estimate the association between IL-4 rs2243250 polymorphism and gastric cancer susceptibility. All the statistical analyses were performed with Stata 12.0 software.

Results

A total of eleven published case–control studies were identified, including 2,247 gastric cancer patients and 3,370 controls. Overall, no significant association between IL-4 rs2243250 polymorphism and gastric cancer susceptibility was observed in this meta-analysis (T vs C: OR =1.05, 95% CI =0.95–1.17; TT vs CC: OR =1.20, 95% CI =0.89–1.63; CT vs CC: OR =1.14, 95% CI =0.87–1.48; TT + CT vs CC: OR =1.13, 95% CI =0.89–1.44; TT vs CT + CC: OR =1.02, 95% CI =0.88–1.20). Similar results were found in subgroup analyses according to ethnicity and Hardy–Weinberg equilibrium in controls.

Conclusion

This meta-analysis suggests that IL-4 rs2243250 polymorphism may not be associated with gastric cancer susceptibility. Further studies are needed to validate this conclusion.

Significant Association of Interleukin4 Intron 3 VNTR Polymorphism with Susceptibility to Gastric Cancer in a South Indian Population from Telangana

BACKGROUND

Gastric cancer (GC) is the fifth most common malignancy and remains a considerable public health burden worldwide. Genetic variations in genes encoding cytokines and their receptors influence the intensity of the Helicobacter pylori associated inflammatory response, which may contribute to individual differences in the outcome and severity of the disease. Interleukin4 is a typical pleiotropic T helper 2 (Th2) cytokine and is a critical mediator of Th1/Th2 balance. It is involved in the regulation of inflammation-mediated carcinogenesis in human organs, including gastric cancer.

OBJECTIVE

The present retrospective case control study was undertaken to evaluate the association of IL4 intron 3 VNTR polymorphism with the susceptibility to GC in a south Indian population from Telangana state.

MATERIALS AND METHODS

A total of 182 patients with diagnosed GC and 326 randomly selected healthy controls were enrolled in the present study. Genomic DNA was extracted from peripheral leukocytes and genotyping was determined by PCR-based assay. Association between genotypes and gastric cancer was examined by unconditional logistic regression analysis.

RESULT

The variant 3R/2R and 2R/2R genotypes of IL4 exon3 VNTR polymorphism had about 1.9 fold and 3fold increased GC risk, respectively, when compared with 3R/3R genotype [3R/2R vs. 3R/3R: adjusted odds ratio (AOR) = 1.90, 95% confidence interval (CI) = 1.23-2.95 P = 0.004 and 2R/2R vs. 3R/3R: AOR (95%CI) = 2.96 (1.29-6.82), P = 0.011]. Furthermore, a significant increased risk of GC was found for the 2R allele carriers (3R/2R + 2R/2R) compared with the 3R/3R genotype (AOR (95%CI) = 2.04 (1.35-3.10), P = <0.000). The IL4 2R allele frequency was 0.28 among the GC group and 0.18 among the controls, and the difference was statistically significant (P = <0.000).

CONCLUSION

The present study revealed an association of 2R allele and 2R carrier genotypes in the etiopathogenesis of GC in south Indian population.

Association Between IL-4 and IL-6 Expression Variants and Gastric Cancer Among Portuguese Population

Introduction

Multiple studies have reported strong associations between Helicobacter pylori (Hp) inflammation and gastric cancer (GC) development. Altered expressions of pro/anti-inflammatory cytokines have a crucial role in Hp and GC proliferation. Although there are many studies related to cytokines polymorphisms involvement in GC risk, the role of Interleukin-4 (IL-4) and Interleukin-6 (IL-6) in gastric inflammation process is not yet clarified.

Aim

This study aimed to investigate the impact of common IL-4 and IL-6 polymorphisms in GC development risk among Portuguese population.

Methods

A total of 100 GC biopsies (50 with intestinal type, IGC, 50 with diffuse type, DGC) and 50 chronic gastritis cases, used as control group, were included in this case-control study. IL-4 and IL-6 common polymorphisms were genotyped by PCR-SSP, using commercially available kits.

Results

IL-4 low producer genotypes, IL-4-590TT (OR = 6.7; 95% CI 1.4–32.4) and IL-4-1098GG (OR = 4.4; 95% CI 1.7–16.9) were found associated with IGC and DGC, respectively. We also verified that IL-4 TTT haplotype was linked with both IGC (OR = 5.8; 95% CI 2.3–14.4) and DGC (OR = 2.3; 95% CI 1.0–5.5) groups. Concerning IL-6 results, IL-6-174CG genotype showed a higher prevalence among IGC cases (OR = 7.3; 95% CI 2.7–20.3), and IL-6-174CC (OR = 3.8; 95% CI 1.7–8.7) showed upper prevalence within DGC subjects. Finally, IL-6-174/nt565CG haplotype showed a significant association with both IGC (OR = 7.3; 95% CI 2.7–20.3) and DGC (OR = 7.9; 95% CI 4.2–14.9).

Conclusion

IL-6 and IL-4 expression variants seem to have an important role in GC risk mechanisms. This study provides preliminary evidence that IL-4 and IL-6 polymorphisms, although not directly linked to the disease, may be useful tools in the study of this multifactorial disease.

Association between interleukin-4 gene intron 3 VNTR polymorphism and cancer risk

BACKGROUND

Interleukin-4(IL-4) is a critical inflammatory cytokine and has been involved in pathogenesis of cancer. To date, several studies have investigated the association between IL-4 intron 3 variable number of tandem repeats (VNTR) polymorphism and cancer risk in humans; however, the results remain controversial. We performed this meta-analysis to find a more conclusive association between this polymorphism and cancer risk.

METHODS

Eight eligible case-control studies were identified through searching electronic databases, including 1583 cases and 1638 controls. Odds ratio (OR) and corresponding 95% confidence interval (CI) were used to estimate the strength of the association.

RESULTS

The results of overall analyses indicated that the variant RP2 allele was associated with a decreased cancer risk compared with the RP1 allele (RP2/RP2 vs. RP1/RP1, OR = 0.64, 95% CI = 0.44-0.94; RP2/RP2 vs. RP1/RP1 + RP1/RP2, OR = 0.75, 95% CI = 0.60-0.92; RP2 vs. RP1, OR = 0.72, 95% CI = 0.56-0.92). In subgroup analyses stratified by ethnicity, there was evidence in the Asian population for an association between this polymorphism and cancer risk (RP2/RP2 vs. RP1/RP1 + RP1/RP2, OR = 0.79, 95% CI = 0.63-0.99; RP2 vs. RP1, OR = 0.77, 95% CI = 0.61-0.97).

CONCLUSIONS

IL-4 intron 3 VNTR polymorphism could influence the risk of human cancer. Due to the limitations of this meta-analysis, further well-designed and functional researches should be performed to validate our results.

Association Between p21 Ser31Arg Polymorphism and Gastrointestinal Tract Tumor Risk: A Meta-analysis

Human p21 gene is characterized by a polymorphism at codon 31 leading to a Serine-to- Arginine (S/R), two different alleles of p21 Ser31Arg (rs 1801270) polymorphism have been shown to differ significantly in their transcriptional efficiency. More and more investigations are now being carried out to examine a possible link between the p21 Ser31Arg polymorphism and cancer. However, the results were inconclusive. Therefore, we carried out a systematic review and meta-analysis to examine whether this polymorphism is associated with gastrointestinal tract tumor in Asian. Seven studies (n = 2690), comprising 967 cases and 1723 controls in Asian population, were included in our study. The meta-analysis showed significant association between Ser-allele or Ser/Ser genotype and the susceptibility to gastrointestinal tract tumor in overall studies (Ser-allele vs. Arg-allele: OR = 1.17, 95% CI: 1.04-1.31; Ser/Ser vs. Arg/Arg: OR = 1.38, 95% CI: 1.09-1.75; Ser/Ser vs. Arg/Ser: OR = 1.27, 95% CI: 1.05-1.53; Ser/Ser vs. Arg/Ser + Arg/Arg: OR = 1.29, 95% CI: 1.07-1.54). Despite the limitations, the results of the present meta-analysis suggested that, in the p21 Ser31Arg polymorphism, Ser-allele and Ser/Ser genotype might be risk factors for gastrointestinal tract tumor in Asian populations.

Association between TLR2, MTR, MTRR, XPC, TP73, TP53 genetic polymorphisms and gastric cancer: a meta-analysis

OBJECTIVE

The aim of our meta-analyses is to test the association between six genetic polymorphisms and gastric cancer.

METHODS

A systematic search was performed for all the available candidate genes and gastric cancer among several online databases including PubMed, Embase, Web of Science, the Cochrane Library, CNKI and Wanfang online libraries. After a comprehensive screening, a total of six genes were harvested for the current meta-analyses. These genes include TLR2 (-196 to -174 ins>del), MTR (rs1805087), MTRR (rs1801394), XPC (rs2228001), TP73 (G4C14-A4T14), and TP53 (rs1042522).

RESULTS

Altogether 49 comparative studies among 11 776 cases and 18 633 controls were involved in our meta-analyses. TP53 rs1042522 polymorphism was shown to be associated with gastric cancer risk under the dominant model (P=0.02, OR=1.03, 95% CI=1.00-1.05). A subgroup meta-analysis indicated a significant association under dominant model between TP53 rs1042522 and gastric cancer in the Eastern Asians (P=0.03, OR=1.17, 95%=1.02-1.34).

CONCLUSIONS

These results suggest that TP53 rs1042522 polymorphism might contribute to the susceptibility of gastric cancer under the dominant model, especially in Eastern Asians.

Association between IL-4 -590C>T polymorphism and gastric cancer risk

Published studies on the association between interleukin-4 (IL-4) -590C>T polymorphism and gastric cancer risk have yielded conflicting results. Thus, a meta-analysis of published studies was performed to assess the possible association. All eligible studies of -590C>T polymorphism and gastric cancer risk were collected from the PubMed, the Cochrane Library, and the Embase electronic databases. Statistical analyses were performed by Review Manager 5.0 and Stata 11.0. When all groups were pooled, we did not detect a significant association of -590C>T polymorphism with gastric cancer risk. When stratifying for race, there was a significant association between -590C>T polymorphism and decreased gastric cancer risk under dominant model and allelic model in the subgroup of Caucasians. However, significant association was absent in Asians. Based on our meta-analysis, -590C>T polymorphism was associated with a lower gastric cancer risk under dominant model and allelic model in Caucasians. Nevertheless, we suggest that further studies should be made to confirm these findings.

The -590C/T polymorphism in the IL-4 gene and the risk of cancer: a meta-analysis

Interleukin-4 (IL-4) plays an important role in the pathogenesis of cancer. The -590C/T polymorphism in the IL-4 gene has been implicated in susceptibility to cancer, but the results have been inconclusive. The aim of this study was to analyze the association between this polymorphism with the risk of cancer by meta-analysis. PubMed, Embase, CNKI, and Wanfang databases were searched for all publications concerning the association between this polymorphism and cancer risk. Statistical analyses were analyzed by using RevMan 4.2 and STATA10.0 softwares. A total of 8,715 cases and 9,532 controls in 23 case-control studies were included. The results suggested that there was no significant association between IL-4 -590C/T polymorphism and cancer risks (TT + TC vs. CC: OR = 0.97, 95 % CI = 0.90-1.04, P = 0.36). In the subgroup analysis by ethnicity, no significant association was detected in Asians and Caucasians. In the subgroup analysis by cancer types, no significant association was found in gastric cancer and colorectal cancer. The current meta-analysis suggested that the -590C/T polymorphism in the IL-4 gene might not be associated with increased/decreased risk of cancer. The -590C/T polymorphism might be not a risk factor for cancers.

Three common polymorphisms in the IL-4 gene and cancer risk: a meta-analysis involving 5,392 cases and 6,930 controls

Interleukin-4 (IL-4) is a typical pleiotropic T helper 2 (Th2) cytokine. This cytokine is a critical mediator of the Th1/Th2 balance and apoptosis potential and involved in the process of inflammation-mediated carcinogenesis in human organs. IL-4 gene polymorphisms influence IL-4 transcription and have been implicated in cancer risks. However, current published data show conflicts among of them. To assess the relationship between IL-4 polymorphisms and cancer risks, we performed a meta-analysis which includes 14 studies involving 3,562 cancer cases for IL-4 rs2243250 polymorphism, 6 studies involving 2,052 subjects for IL-4 rs2070874 polymorphism, and 5 studies involving 791 subjects for IL-4 intron-3 polymorphism. As for rs2243250 polymorphism, no significant association of cancer risk was found in the overall analysis. When stratified by cancer type, we observed that the IL-4 rs2243250 polymorphism was significantly associated with decreased oral cancer risk and increased renal cell cancer risk (for oral cancer, TT vs. CC: odds ratio (OR) = 0.40, 95 % confidence interval (95 % CI) 0.19-0.84, P heterogeneity = 0.662, P = 0.016; TT/CT vs. CC: OR = 0.45, 95 % CI 0.22-0.94, P heterogeneity = 0.407, P = 0.033; and for renal cell cancer, TT vs. CC: OR = 1.98, 95 % CI 1.06-3.69, P heterogeneity = 0.535, P = 0.031; TT vs.

CC/CT

OR = 1.43, 95 % CI 1.05-1.95, P heterogeneity = 0.959, P = 0.022). For rs2070874 and intron-3 polymorphisms, no significant association of cancer risk was found in the overall analysis. However, in the subgroup analysis by source of controls and ethnicities, a significant association between cancer risk and rs2070874 polymorphism was found in population-based studies (A allele vs. G allele: OR = 1.18, 95 % CI 1.03-1.35, P heterogeneity = 0.621, P = 0.0172; AA vs.

AG/GG

OR = 1.23, 95 % CI 1.03-1.47, P heterogeneity = 0.196, P = 0.024) and Caucasian populations (A allele vs. G allele: OR = 1.24, 95 % CI 1.03-1.48, P heterogeneity = 0.925, P = 0.022), but not in Asian populations. Taken together, our results indicated that IL-4 rs2243250 polymorphism was associated with decreased oral cancer risk in both the homozygote contrasts and the dominant genetic model, as well as increased renal cell cancer risk in both the homozygote contrasts and the recessive genetic model. The A allele of rs2070874 polymorphism in the IL-4 gene may be a risk factor for cancer development among Caucasians. Further larger, preferably prospective studies are needed to confirm these results.

Pro variant of TP53 Arg72Pro contributes to gastric cancer risk in Asians: evidence from a meta-analysis

BACKGROUND

Previous studies investigating the association between TP53 Arg72Pro polymorphism and gastric cancer (GC) risk in Asian population have reported controversial results. Thus, a meta-analysis was performed.

METHODS

A comprehensive literature search was conducted and 17 case-control studies were finally included, involving a total of 5,990 GC cases and 6,812 controls. Subgroup analyses were performed by the sample size.

RESULTS

Meta-analysis of all 17 studies showed variant genotypes of TP53 Arg72Pro to be associated with an elevated GC risk in three genetic comparison models (OR(Pro vs. Arg)=1.13, 95%CI 1.03-1.25, P(OR)=0.01; OR(Homozygote comparison model)=1.33, 95%CI 1.07-1.64, P(OR)=0.009; OR(Dominant genetic model)=1.13, 95%CI 1.05-1.22, P(OR)=0.002). Besides, a more obvious association was observed after the heterogeneity was decreased (all P values less than 0.001). This association was further identified by both subgroup and sensitivity analyses.

CONCLUSIONS

This meta-analysis suggests the Pro variant of TP53 Arg72Pro contributes to gastric cancer risk in Asians.

Alterations of the TP53 gene in gastric and esophageal carcinogenesis

TP53 genes is one of more important tumor suppressor gene, which acts as a potent transcription factor with fundamental role in the maintenance of genetic stability. The development of esophageal and gastric cancers is a multistep process resulting in successive accumulation of genetic alterations that culminates in the malignant transformation. Thus, this study highlights the participation of the main genetic alterations of the TP53 gene in esophageal and gastric carcinogenesis. Among these changes, high frequency of TP53 mutations, loss of heterozygosity (LOH), overexpression of the p53 protein, and consequently loss of p53 function, which would be early events in esophageal and gastric cancers, as well as an important biomarker of the prognosis and treatment response. Furthermore, Single Nucleotide Polymorphisms (SNPs) of TP53 have been implicated in the development and prognosis of several cancers, mainly TP53 codon 72 polymorphism whose role has been extensively studied in relation to susceptibility for esophageal and gastric cancer development.

Association between p21 Ser31Arg polymorphism and cancer risk: a meta-analysis

P21 (CDKN1A), a key cell cycle regulatory protein that governs cell cycle progression from G1 to S phase, can regulate cell proliferation, growth arrest, and apoptosis. The Ser31Arg polymorphism is located in the highly conserved region of p21 and may encode functionally distinct proteins. Although many epidemiological studies have been conducted to evaluate the association between the p21 Ser31Arg polymorphism and cancer risk, the findings remain conflicting. This meta-analysis with 33 077 cases and 45 013 controls from 44 published case-control studies showed that the variant homozygous 31Arg/Arg genotype was associated with an increased risk of numerous types of cancers in a random-effect model (homozygote comparison: OR = 1.17, 95% CI = 0.99 to 1.37, P = 0.0002 for the heterogeneity test; recessive model comparison: OR = 1.16, 95% CI = 1.01 to 1.33, P = 0.0001 for the heterogeneity test). Stratified analysis revealed that increased cancer risk associated with the 31Arg/Arg genotype remained significant in subgroups of colorectal cancer, estrogen-related cancer, Caucasians, population-based studies, studies with matching information or a larger sample size. Heterogeneity analysis showed that tumor type contributed to substantial between-study heterogeneity (recessive model comparison: Χ(2) = 21.83, df = 7, P = 0.003). The results from this large-sample sized meta-analysis suggest that the p21 31Arg/Arg genotype may serve as a potential marker for increased cancer risk.

Associations between P53 Arg72Pro and development of digestive tract cancers: a meta-analysis

BACKGROUND AND AIMS

The relationships between P53 Arg72Pro and risks of digestive tract cancers have been extensively studied, and conclusive results were unavailable.

METHODS

Fifty three case-control studies were included through searching the databases of Medline, Embase and CNKI (up to August 2010). The odds ratio (OR) and 95% confidence interval (95% CI) were used to investigate the strength of the associations.

RESULTS

The results showed that there were no overall associations between P53 Arg72Pro and risks of digestive tract cancers. Subgroup analyses showed that P53 Arg72Pro was associated with risk of gallbladder and pancreatic cancer (OR [95% CI]: 1.44 [1.13-1.83] for Pro carriers vs. ArgArg). In addition, subgroup analyses also suggested that the Pro allele was associated with increased risks of digestive tract cancers among Asians (1.19 [1.01-1.42] for ProPro vs. ArgArg). Meanwhile, Pro allele was also suggested to be associated with increased risk of gastric cancer (1.33 [1.02-1.74] for ProPro vs. ArgPro for diffuse type of gastric cancer and 1.29 [1.05-1.57] for ProPro vs. Arg carriers for gastric cardia cancer) and colorectal cancer (1.26 [1.05-1.51] for ProPro vs. ArgPro for population-based case-control studies; 1.43 [1.09-1.87] for ProPro vs. ArgArg for colon cancer; 1.49 [1.09-2.06] for ProPro vs. ArgArg for rectal cancer and 2.22 [1.44-3.44] for ProPro vs. ArgArg for early stage of colorectal cancer).

CONCLUSIONS

This meta-analysis suggests that Pro allele in P53 Arg72Pro is significantly associated with the increased risks of digestive tract cancers, especially for Asians, and for gastric cancer, colorectal cancer and gallbladder and pancreatic cancer.

Influence of interleukin polymorphisms on development of gastric cancer and peptic ulcer

Pro-inflammatory cytokines are produced in the gastric mucosa by inflammatory cells activated by chronic Helicobacter pylori (H. pylori) infection. Polymorphisms of these cytokine genes are associated with individual differences in gastric mucosal cytokine mRNA level, which result in differences in gastric mucosal inflammation, acid inhibition and gastroduodenal disease risk in response to H. pylori infection. Although polymorphisms of interleukin (IL)-1B, IL-1RN and TNF-A have been reported to relate well with gastric cancer and peptic ulcer risk, those of IL-2, IL-4, IL-6 and IL-8 genes are unclear. In combined analyses using data from previous studies, we found that the risk of gastric non-cardia cancer development was significantly associated with IL-4-168 C allele (OR: 0.81, 95% CI: 0.69-1.00) and IL-4-590 T allele carrier status (0.61, 0.53-0.73), and IL-6-174 G/G genotype (2.02, 1.31-3.10). In peptic ulcer development, IL-2-330 G and IL-4-590 T allele carriers had a significantly decreased risk (0.37, 0.27-0.50 and 0.58, 0.34-0.99, respectively). Moreover, IL-2, IL-4, IL-6 and IL-8 gene genotypes prevalence differs among populations. The inflammatory cytokine gene polymorphisms (e.g. IL-4-590 and IL-6-572 for gastric cancer, and IL-4-590, IL-6-572 and IL-8-251 for peptic ulcer) have a more potent influence on development of gastroduodenal diseases in Western than East Asian populations. These cytokine gene polymorphisms, as well as those of IL-1B, IL-1RN and TNF-A, may be used to identify groups at higher risk of gastric cancer and peptic ulcer, and those suitable for their prevention by H. pylori eradication therapy in Western populations.

Cell proliferation-related genetic polymorphisms and gastric cancer risk: systematic review and meta-analysis

Apart from Helicobacter pylori infection and lifestyle factors, host genetic susceptibility has been suggested to contribute to individual variation in gastric cancer risk as well. Aiming to evaluate the associations between host cell proliferation-related genetic polymorphisms and gastric cancer susceptibility, we reviewed the related studies published until 15 September 2008 and quantitatively summarized the associations of the most widely studied polymorphisms (TP53 Arg72Pro, L-myc EcoRI) using meta-analysis. Fifty-five eligible studies were included in this review. Twenty-three polymorphisms significantly related to gastric cancer risk in at least one study were identified. Polymorphisms determining higher levels of growth factors, which are important for tissue repair, were recently observed to be associated with reduced risk of gastric cancer. In the meta-analysis, TP53 72Pro was associated with increased risk of diffuse gastric cancer among Asians (OR, 1.44; 95% CI, 1.04-1.99), but decreased risk of intestinal gastric cancer among Caucasians (OR, 0.56; 95% CI, 0.36-0.89). This review suggests that cell proliferation-related genetic polymorphisms could be candidate biomarkers of gastric cancer risk, but current evidence for the use for risk stratification is still very limited. Modestly significant associations in meta-analyses stratified by population or type of gastric cancer may be observed by chance because of the limited number of studies and small sample size. Larger studies are warranted to clarify the effect of cell proliferation-related genetic polymorphisms on gastric carcinogenesis.

Soybean product intake modifies the association between interleukin-10 genetic polymorphisms and gastric cancer risk

In this study, our aim was to investigate the association of inflammation-related genetic polymorphisms and gastric cancer risk and to examine whether the combined effect of soybean product intake modified cancer risk. Eighty-four incident gastric cancer cases and 336 matched controls were selected from the Korean Multi-Center Cancer Cohort. We selected 14 single nucleotide polymorphisms (SNP) from 5 genes [interleukin (IL)-1beta, IL-2, IL-4, IL-8, and IL-10] and used unconditional logistic regression model to calculate the odds ratios (OR) and 95% CI adjusting for H. pylori seropositivity, smoking, age, sex, enrollment year, and residential area. The risk for gastric cancer in relation to genetic polymorphisms and haplotypes were assessed according to soybean product intake levels. Although no single SNP effect was found, the combined effect between IL-10 gene variants of -592 GG/GA, -819 TC/CC, or -1082 AG/GG and low intake of soybean products had an increased risk for gastric cancer compared with the group with no risk gene variants and a high intake of soybean products (OR [95% CI] = 2.82 [1.04-7.62], 2.75 [1.02-7.44], and 4.34 [1.51-12.5], respectively). Among the low-soybean product intake group, IL-10 CCG haplotype had an increased risk of gastric cancer (OR = 3.38 [1.40-8.13]) relative to the ATA haplotype. Our results suggest that the association between IL-10 genetic polymorphisms and gastric cancer risk was modified by soybean product intake.

Genetic variants in T helper cell type 1, 2 and 3 pathways and gastric cancer risk in a Polish population

Host immune responses are known determinants of gastric cancer susceptibility. We previously reported an increased gastric cancer risk associated with common variants of several T helper type 1 (Th1) cytokine genes in a population-based case-control study in Warsaw, Poland. In the present study, we augmented our investigation to include additional Th1 genes as well as key genes in the Th2 and Th3 pathways. Analysis of 378 cases and 435 age- and sex-matched controls revealed associations for polymorphisms in the Th1 IL7R gene and one polymorphism in the Th2 IL5 gene. The odd ratios (ORs) for IL7R rs1494555 were 1.4 [95% confidence interval (CI), 1.0-1.9] for A/G and 1.5 (95% CI, 1.0-2.4) for G/G carriers relative to A/A carriers (P = 0.04). The ORs for IL5 rs2069812 were 0.9 (95% CI, 0.7-1.3) for C/T and 0.6 (95% CI, 0.3-1.0) T/T carriers compared with C/C carriers (P = 0.03). These results suggest that IL5 rs2069812 and IL7R rs1389832, rs1494556 and rs1494555 polymorphisms may contribute to gastric cancer etiology.

Comprehensive assessment of P21 polymorphisms and lung cancer risk

The purpose of this study is to comprehensively evaluate potential functional polymorphisms in the P21 gene in relation to the risk of lung cancer. We first determined the frequencies of P21 polymorphisms in 27 healthy Koreans, and then examined three polymorphisms (-2266G > A, S31R, and IVS2 + 16G > C), based on their frequencies and haplotype-tagging status, in a case-control study. Individuals with at least one -2266A allele were at a significantly decreased risk of lung cancer compared with those harboring the -2266 GG genotype [adjusted odds ratio (OR) = 0.71, 95% confidence interval (CI) = 0.53-0.95, P = 0.02). The haplotypes (ht2-4) carrying 31R or IVS2 + 16C alleles were associated with a significantly decreased risk of lung cancer compared with the haplotype 31S/IVS2 + 16G, which carried wild-type alleles at both loci (adjusted OR = 0.65, 95% CI = 0.50-0.83, P = 0.007)]. When the -2266A allele and ht2-4 were considered to be protective alleles, the risk of lung cancer decreased in a dose-dependent manner as the number of protective alleles increased (P = 0.0002). These results suggest that a combined analysis of these three P21 polymorphisms might better predict the risk of lung cancer than the analysis of a single polymorphism.

Association of interferon-gamma and interleukin-4 gene polymorphisms with susceptibility to brucellosis in Iranian patients

Activation of macrophages and their antimicrobial activities by interferon-gamma (IFN-gamma) plays a crucial role in controlling Brucella infection. Interleukin-4 (IL-4) antagonizes the macrophage activity effects of IFN-gamma and thus inhibits cell-mediated immune reactions. Given that the production of IFN-gamma and IL-4 are under genetic control, we investigated the relationship between these two cytokine gene polymorphisms and the susceptibility to brucellosis. Hundred and ninety-five patients with brucellosis and 91 healthy animal husbandmen who owned infected animals and consumed their contaminated dairy products were selected to participate in this study. All individuals were genotyped for IFN-gamma and IL-4 gene polymorphisms at positions +874 and -590, respectively. Results showed that IFN-gammaAA genotype was significantly more prevalent (P =0.03) and IL-4CC genotype was significantly less frequent (P =0.034) in the patient group compared to the control group. Also, the frequency of IFN-gamma/IL-4 combination of genotype (IFN-gammaTT/IL-4CC) and allele (IFN-gammaT/IL-4C) were significantly higher in the controls than in the patients (P =0.033 and P =0.0035, respectively). Data suggest that individuals who have IFN-gammaAA genotype are more susceptible, and those who carry IL-4CC genotype are more resistant to brucellosis. We also suggest that individuals who carry IFN-gammaT/IL-4C or IFN-gammaTT/IL-4CC can be more resistant to Brucella infection.

Genetic factors involved in the development of Helicobacter pylori-related gastric cancer

Developmental process to gastric cancer by Helicobacter pylori infection consists of three steps: (1) H. pylori infection; (2) gastric atrophy development; and (3) carcinogenesis. In each step, genetic traits may influence the process, interacting with lifestyle. In the step of H. pylori infection, two lines of genetic polymorphisms were assumed: one influencing gastric acid inhibition interacting with smoking, and the other concerning innate immune response attenuation. The former includes functional polymorphisms of IL-1B (C-31T or tightly linked T-511C), and TNF-A (T-1031C and C-857T), and the latter possibly includes NQO1 C609T. In the step to gastric atrophy, polymorphisms pertaining to the signal transduction from cytotoxin-associated gene A (PTPN11 A/G at intron 3) and to T-cell responses (IL-2 T-330G and IL-13 C-1111T) were hypothesized. There are a limited number of epidemiological genotype studies on the final step of literal carcinogenesis, potentially interacting with smoking, a low vegetable and fruit intake, and salty foods, the well-documented risk factors. In past case-control studies on the associations between genotype and gastric cancer risk, the cases consisted of H. pylori-related and unrelated gastric cancer patients and the controls consisted of individuals including the uninfected (H. pylori unexposed and exposed) and the infected with and without gastric atrophy. Accordingly, it was not clear whether the observed risk was for H. pylori-related or -unrelated gastric cancer, nor which step was involved in the observed associations even when nearly all cases were H. pylori-related. In order to elucidate the genetic traits of H. pylori-related gastric cancer, stepwise evaluation will be required.