Genetic variation in adipokine genes and risk of colorectal cancer

Leptin receptor Gln223Arg and Lys109Arg polymorphisms may be associated with HBV-related hepatocellular carcinoma risk: A system review and meta-analysis

Increasing evidence has suggested a strong association of hepatocellular carcinoma (HCC) susceptibility and Gln223Arg (rs1137101) and Lys109Arg (rs1137100) polymorphisms in leptin receptor (LEPR) genes. To provide a quantitative assessment for such correlation, we reviewed all related systems and conducted meta-analysis for case and control researches. A literature search of Web of Science, EMBASE, PubMed, Scopus as well as China National Knowledge Infrastructure databases was collected. 95% confidence intervals (95% CIs) together with odds ratios (ORs) were calculated. Five case-control researches consisting of 1323 cases and 1919 control cases were incorporated into meta-analysis. Researches indicated A-allelic and AA genotype of rs1137101 were substantially related to boosted susceptibility of hepatitis B virus (HBV)-related HCC (mutant model, OR = 1.81, 95% CI = 1.36-2.41, p < .001; allelic model, OR = 1.55, 95% CI = 1.32-1.83, p < .001). On the contrary, we observed GG genotype of rs1137101 substantially related to reduced risk of HBV-related HCC (wild model, OR 0.59, 95%CI = 0.46-0.75, p < .001). We observed AA genotype of rs1137100 relevant to boosted HCC risk (mutant model, OR = 1.51, 95%CI = 1.14-2.01, p = .005) as well as in those with HBV-related HCCs (homozygous model, OR = 2.12, 95%CI = 1.49-3.02, p < .001; mutant model, OR = 1.67, 95%CI = 1.23-2.26, p = .001). G-allele and AA genotype of rs1137101 might be in connection with boosted HBV-related HCC susceptibility, and wild-type GG genotype might prevent diseases. AA genotype of rs1137100 might also improve HBV-related HCC susceptibility. Such conclusions ought to be validated by larger and better-designed researches.

An Updated Review of Resistin and Colorectal Cancer

Resistin is one of the most important adipokines, and its role lies mainly in controlling insulin sensitivity and inflammation. However, over the last years, the study of resistin gained increased popularity since it was proved that there is a considerable relationship between high levels of resistin and obesity as well as obesity-induced diseases, including diabetes, cardiovascular disorders, and cancer. Regarding cancer risk, circulating resistin levels have been correlated with several types of cancer, including colorectal, breast, lung, endometrial, gastroesophageal, prostate, renal, and pancreatic cancer. Colorectal cancer is regarded as a multi-pathway disease. Several pathophysiological features seem to promote colorectal cancer (CRC) such as chronic inflammation, insulin resistance, and obesity. Even though the molecular mechanisms involved in CRC development remain rather vague, it is widely accepted that several biochemical factors promote CRC by releasing augmented pro-inflammatory cytokines, like IGF-I, insulin, sex-steroid hormones, and adipokines. A wide range of research studies has focused on evaluating the impact of circulating resistin levels on CRC risk and determining the efficacy of chemotherapy in CRC patients by measuring resistin levels. Moreover, significant outcomes have emerged regarding the association of specific single nucleotide polymorphisms (SNPs) in the resistin gene and CRC risk. The present study reviewed the role of circulating resistin levels in CRC development and shed light on specific resistin gene SNPs implicated in the disease's development. Finally, we analyzed the impact of resistin levels on the effectiveness of chemotherapy and further discussed whether resistin can be regarded as a valuable biomarker for CRC prognosis and treatment. Resistin is one of the most important adipokines, and its role lies mainly in controlling insulin sensitivity and inflammation. However, over the last years, the study of resistin gained increased popularity since it was proved that there is a considerable relationship between high levels of resistin and obesity as well as obesity-induced diseases, including diabetes, cardiovascular disorders, and cancer. This review discusses the aberrant expression of resistin and its receptors, its diverse downstream signaling, and its impact on tumor growth, metastasis, angiogenesis, and therapy resistance to support its clinical exploitation in biomarker and therapeutic development.

Serum Leptin Receptor and the rs1137101 Variant of the LEPR Gene Are Associated with Bladder Cancer

Globally, bladder cancer (BC) is one of the ten most common tumors. Obesity is a worldwide problem associated with an increased BC risk. Considering that levels of leptin and/or its receptor are often deregulated in obese individuals, we hypothesized that they could contribute to BC. To test this hypothesis, we utilized a case-control study in which 116 patients with a confirmed diagnosis of BC and 116 controls were recruited. The serum levels of leptin and leptin receptor were measured. Patients and controls were also genotyped for SNPs in the LEP (rs7799039, rs791620, and rs2167270) and LEPR genes (rs1137100, rs1137101, and rs1805094). The univariate analysis indicated that BC patients had significantly higher levels of leptin and lower levels of leptin receptor (p < 0.05). Moreover, rs7799039 of LEP and rs1137101 of LEPR were associated with BC (p < 0.05). In the multivariate analysis, leptin receptor levels were protective (OR: 0.98, 95% CI = 0.97-0.99, p = 0.002) while the GG genotype of rs1137101 of LEPR increased BC risk (OR: 3.42, 95% CI = 1.27-9.20, p = 0.02). These findings highlight that lifestyle changes could be useful in preventing BC and that disturbances in energy metabolism could play a role in the pathobiology of BC.

The first combined meta‐analytic approach for elucidating the relationship of circulating resistin levels and RETN gene polymorphisms with colorectal and breast cancer

Background

Evidence suggests that circulating resistin levels are altered in colorectal cancer (CRC) and breast cancer (BC). Again, polymorphisms in resistin-encoding gene RETN have been evaluated in CRC and BC. However, there is a scarcity of data establishing the relationship of resistin and RETN polymorphisms (rs1862513 and rs3745367) with these cancers. This study aimed to analyze the relationship of resistin levels and RETN polymorphisms with CRC and BC in a combined meta-analytic approach.

Main body of the abstract

After a comprehensive online literature search, screening and eligibility check, 41 articles (31 with resistin level and 10 with RETN polymorphisms) were retrieved for meta-analyses. The mean difference (MD) of resistin was calculated and pooled to investigate the effect sizes with a 95% confidence interval (CI), and the connection of genetic polymorphisms was analyzed with an odds ratio (OR) and 95% CI. The analysis showed that resistin level is significantly higher in CRC (MD = 3.39) and BC (MD = 3.91) patients. Subgroup analysis in CRC showed significantly higher resistin in serum (MD = 4.61) and plasma (MD = 0.34), and in BC, a significantly elevated resistin level was reported in premenopausal (MD = 7.82) and postmenopausal (MD = 0.37) patients. Again, RETN rs1862513 showed a significantly strong association with CRC (codominant 1—OR 1.24, codominant 2—OR 1.31, dominant model—OR 1.25, and allele model—OR 1.16) and with BC (codominant 2—OR 1.51, codominant 3—OR 1.51, recessive model—OR 1.51, and allele model—OR 1.21). RETN rs3745367 did not show any association with these cancers.

Short conclusion

Overall, our analysis indicates that higher circulating resistin levels are associated with an elevated risk of CRC and premenopausal and postmenopausal BC. Besides, rs1862513 in RETN gene is significantly connected with both CRC and BC.

Investigation of Leptin G19A polymorphism with bladder cancer risk: A case-control study

Background

A host of studies show Leptin (LEP) G19A polymorphism is correlated with the risk of various cancers, but the connection of this polymorphism with bladder cancer (BC) risk has not been reported.

Materials and methods

This association was in explored in a case‐control study involving 355 BC cases and 435 controls (all Chinese Han). Polymerase chain reaction‐restriction fragment length polymorphism was conducted to genotype LEP G19A polymorphism. Analyses of allele and genotype distribution were evaluated using chi‐square test. Continuous data were assessed by an independent samples t test or one‐way ANOVA test. Odds ratio (OR) and 95% confidence interval (CI) were determined by logistic regression.

Results

LEP G19A polymorphism was significantly associated with a lower risk of BC (AA vs GG: adjusted OR, 0.40, 95% CI, 0.20‐0.83, P = .013; AA + GA vs GG: adjusted OR, 0.70, 95% CI, 0.52‐0.93, P = .015; AA vs GA + GG: adjusted OR, 0.45, 95% CI, 0.22‐0.91, P = .026). In addition, A allele was associated with decreased risk for BC (A vs G: OR, 0.70, 95% CI, 0.55‐0.89, P = .003). Stratified analyses by females, non‐drinkers, and non‐smokers all returned considerable relations. Furthermore, LEP G19A polymorphism was correlated with tumor size, tumor node metastasis, and distant metastasis in BC patients.

Conclusions

LEP G19A polymorphism is associated with a less risk of BC.

Investigation of leptin receptor rs1137101 G>A polymorphism with cancer risk: evidence from 35936 subjects

Leptin receptor (LEPR) signaling may be involved in promoting angiogenesis and proliferation, inhibiting apoptosis and playing a vital role in the progression of carcinogenesis. A number of studies have focused on the association of LEPR rs1137101 variants with susceptibility of cancer, however, the observed results were controversial. We searched literature on the relationship of LEPR rs1137101 G>A polymorphism with cancer risk by using PubMed and Embase databases, covering all publications up to 14 October 2018. In total, 44 case–control studies with 35,936 subjects were included. After combining all eligible studies, we identified null relationship between LEPR gene rs1137101 G>A polymorphism and overall cancer risk [A vs. G: odds ratio (OR ) =  0.97, 95% confidence interval (CI ) =  0.89–1.06, P = 0.547; AA vs. GG: OR  =  0.93, 95% CI  =  0.78–1.13, P = 0.476; AA/GA vs. GG: OR  =  0.99, 95% CI  =  0.91–1.09, P= 0.890 and AA vs. GA/GG: OR  = 0.92, 95% CI  =  0.82–1.04, P= 0.198]. However, in a subgroup analysis, there was an increased susceptibility of oral and oropharyngeal cancer in AA vs. GA/GG genetic model (OR, 1.83; 95% CI, 1.01–3.33; P=0.048). Considering the limited participants were included, the findings might be underpowered. Sensitivity analysis identified that any independent study omitted did not materially influence the pooled ORs and CIs. The results of publication bias detection showed that there was no evidence of bias. In summary, this analysis indicates that no significant association of cancer risk was identified to be correlated with rs1137101 G>A variants, even in stratified analyses.

Leptin rs7799039 (G2548A) polymorphism is associated with cancer risk: a meta-analysis involving 25,799 subjects

Background: Leptin (LEP) is a human analogous form of the mouse obese gene and plays a critical role in energy expenditure as well as the progression of carcinogenesis. Many studies exploring the relationship between the LEP rs7799039 (G2548A) polymorphism and cancer risk have observed controversial results. To extensively evaluate this potential association, we conducted this meta-analysis.

Methods: All eligible studies published up to August 2018 on the relationship between the LEP rs7799039 G>A polymorphism and cancer risk were obtained by searching PubMed, EMBASE, and the China Biology Medicine databases. The association of LEP rs7799039 G>A polymorphism with cancer risk was evaluated by crude ORs together with their 95% CI's.

Results: Thirty-one case–control studies involving 25,799 subjects were included for meta-analysis. We identify a significant correlation with an overall cancer risk when these eligible case–control studies were pooled for analysis: for AA vs GG: an OR = 1.22, 95% CI = 1.01–1.48, P = 0.042 and for AA/GA vs GG: an OR = 1.16, 95% CI = 1.02–1.33, P = 0.026. A significant association was also detected in Asians, prostate cancer, other cancers, and hematopoietic malignancy subgroups. Sensitivity analysis was conducted by deleting an individual study in turn and calculation of the pooled ORs and CIs of the remainders. The results of sensitivity analyses indicated that no eligible study influenced the pooled ORs and CIs materially. Begg’s and Egger’s tests revealed that there was no evidence of publication bias.

Conclusion: In conclusion, our study suggests that the LEP rs7799039 G>A polymorphism might contribute to the development of cancer. In order to further verify or refute our findings, large and well-designed epidemiological studies are needed.

LEPR polymorphisms and haplotypes in Mexican patients with colorectal cancer

INTRODUCTION

Obesity and colorectal cancer could be linked by adipocytokines, which are proteins associated with cell proliferation. High levels of the adipocytokine leptin promote the development of colorectal cancer through its receptor.

OBJECTIVE

To determine the association between c.326A>G and c.668A>G LEPR gene polymorphisms and colorectal cancer.

MATERIALS AND METHODS

DNA was extracted from the peripheral blood of 147 patients with sporadic colorectal cancer and 134 healthy people. Genotypes were obtained by PCRRFLP and the association was determined by the odds ratio (OR) test using the SPSS™, version 10.0, program. Haplotype frequencies and linkage disequilibrium were estimated by the Arlequin, version 3.5, software.

RESULTS

Both polymorphisms were in Hardy-Weinberg equilibrium. Only the c.326A>G heterozygous genotype revealed an increased risk for colorectal cancer development (OR=1.81, 95% CI=1.04-3.16, p=0.04). The AG haplotype showed a significant association with colorectal cancer (OR=0.58, 95% CI=0.35-0.96, p<0.03). Linkage disequilibrium between the variants was only evident for the patients group (r2=0.36).

CONCLUSION

Our results suggest that AG individuals heterozygous for the c.326A>G LEPR variant have a higher risk of colorectal cancer development whereas the AG haplotype (c.326A/c.668G) has a protective effect in the Mexican population.

Association between rs1862513 and rs3745367 Genetic Polymorphisms of Resistin and Risk of Cancer: A Meta-Analysis

The present study aimed to assess any associations between resistin gene (RETN) polymorphisms and cancer susceptibility by conducting a meta-analysis. A comprehensive literature search was performed with PubMed, Web of Science, Scopus and Google Scholar for relevant studies published before April 2018. For the rs1862513 polymorphism, data from 9 studies covering 1,951 cancer patients and 2,295 healthy controls were included in this meta-analysis. Pooled odds ratios (ORs) with 95% confidence intervals (CIs) were calculated. Our meta-analysis revealed that this RETN polymorphism significantly increased the risk of cancer in codominant (OR=1.23, 95% CI= 1.01-1.50, p=0.04, CG vs CC; and OR=1.25, 95% CI= 1.03-1.53, p=0.03, GG vs CC), dominant (OR=1.19, 95% CI= 1.05-1.35, p=0.006, CG+GG vs CC), and allele (OR=1.14, 95% CI= 1.00-1.30, p=0.04, G vs C) inheritance genetic models. Stratification analysis by cancer type revealed that the rs1862513 variant significantly increased the risk of colorectal and breast cancer, and that cancer overall in Caucasians (OR=1.22, 95% CI= 1.04-1.43, p=0.02, CG+GG vs CC; OR=1.18, 95% CI= 1.04-1.34, p=0.01, G vs C). The data revealed no correlation between the rs3745367 polymorphism and cancer risk. Further well-designed studies with larger sample sizes and different ethnicities are warranted to validate the present findings.

Association of RETN and CAP1 SNPs, Expression and Serum Resistin Levels with Breast Cancer in Mexican Women

BACKGROUND

Breast cancer is the most common cancer in women worldwide. Approximately 70% of female breast cancer patients have a body mass index (BMI) >25. In obesity, adipose tissue secretes additional resistin, which prompts a proinflammatory effect through its action on adenylate cyclase-associated protein 1 (CAP1). Several studies have associated the RETN gene single nucleotide polymorphism (SNP) rs1862513 (-420C<G) with serum resistin levels and breast cancer. The CAP1 gene SNP rs35749351 (missense, Arg294His), located in the extracellular domain, has not previously been studied in cancer. These two SNPs, the mRNA expression levels of the two alleles for each of the cognate genes, and the serum resistin levels were compared between patients and controls to determine their association with breast cancer in Mexican women in this study.

MATERIALS AND METHODS

This study included 308 controls and 100 female patients with breast cancer. SNPs were detected by PCR-RFLP from DNA isolated from peripheral blood. Gene expression was performed with hydrolysis probes in tumor tissue. Resistin levels were quantified from serum samples by ELISA.

RESULTS

The RETN rs1862513CG/GG and CAP1 rs35749351GA/AA genotypes were associated with 1.61 and 2.193-fold increased risks of breast cancer, respectively, compared with the CC and GG genotypes. Similarly, carriers of the G allele of rs1862513 and the A allele of rs35749351, had 1.51 and 2.217-fold increased risks of breast cancer compared with the C and G alleles, respectively. The rs1862513GG/rs35749351AA genotype combination increased breast cancer risk by twofold. Serum resistin levels in postmenopausal breast cancer women were higher compared with postmenopausal controls. Tissue CAP1 expression showed differences with regard to molecular subtypes and metastases.

CONCLUSION

The RETN and CAP1 polymorphisms and gene expression may be potential biomarkers for breast cancer risk.

ADIPOQ polymorphisms are associated with changes in obesity-related traits in response to aerobic training programme in women

Among genetic variants of the ADIPOQ gene +276 G>T (rs1501299) and –11377 G>C (rs266729) are the most frequently investigated polymorphisms which were described in the context of genetic conditioning for a predisposition to obesity. However, the information of polymorphisms’ potential modifying effect on obesity-related traits achieved through training procedures are still unknown. DNA was extracted from buccal cells donated by the 201 participants and genotyping was carried out using real-time PCR. The genotype distribution was examined in a group of women measured for chosen traits before and after the completion of a 12-week training programme. Our results suggest that the ADIPOQ genotypes analyzed individually or in combination can modulate training-induced body mass measurements changes: after the training programme, carriers of rs1501299 T allele and rs266729 C allele were characterized by a greater reduction in fat mass percentage (FM), fat mass, and body mass. Moreover, the ADIPOQ polymorphisms were associated with changes in lipid profile in response to training. Additionally, we showed three main effects of genotypes for the FM, LDL-C (rs266729), and TBW (rs1501299). Our study indicate that the both polymorphisms are associated with changes in obesity-related traits in response to 12-week aerobic training programme in Caucasian women. From this evidence, it could be concluded that rs1501299 G and rs266728 G variants may be considered as disadvantageous factor in the context of training-induced effects on body mass traits.

Associations of adiponectin receptor 2 (AdipoR2) gene polymorphisms and AdipoR2 protein expression levels with the risk of colorectal cancer: A case-control study

The aim of the present study was to investigate the associations between adiponectin receptor 2 (AdipoR2) gene polymorphisms, AdipoR2 protein expression levels and the risk of colorectal cancer (CRC). From April 2012 to May 2015, 281 CRC patients (case group) admitted to the China-Japan Friendship Hospital and 325 healthy control subjects (control group) were recruited for the study. Peripheral venous blood samples were collected and the DNA was extracted. Genotyping was performed using denaturing high-performance liquid chromatography in the condition of partial degeneration. Linkage disequilibrium and haplotype were analyzed using SHEsis analysis software. AdipoR2 protein expression levels were detected by immunohistochemistry and logistic regression analysis was performed to determine the risk factors of CRC. The distribution of the TT genotype of AdipoR2 rs10773989 and the CC genotype of AdipoR2 rs1044471 was higher in the case group than in the control group (P<0.05). The AdipoR2 rs10773989 polymorphism was associated with the degree of tumor infiltration in CRC (P<0.05) and the AdipoR2 rs1044471 polymorphism was associated with the degree of differentiation and Dukes' staging in CRC (P<0.05). The CT haplotype was identified as a protective factor, while the TC haplotype was a risk factor in a healthy population. AdipoR2 protein expression was associated with the degree of differentiation, Dukes' staging, degree of tumor infiltration and lymphatic metastasis in CRC (all P<0.05). Logistic regression analysis demonstrated that the TT genotype of AdipoR2 rs10773989 and CC genotype of AdipoR2 rs1044471 were independent risk factors for CRC. The AdipoR2 rs10773989 and rs1044471 polymorphisms may be correlated with the susceptibility to CRC. In addition, the TC haplotype and AdipoR2 positive expression may increase the risk of CRC.

Association of ADIPOQ and ADIPOR variants with risk of colorectal cancer: A meta-analysis

Numerous epidemiological studies have studied the association of adiponectin (ADIPOQ) gene and adiponectin receptor (ADIPOR) gene polymorphisms with risk of colorectal cancer (CRC), but the outcomes were incomplete and inconsistent. Therefore, we conducted a meta-analysis to assess the associations systematically. All eligible case-control studies published up to Jan. 2015 were searched from PubMed, the Cochrane library, Elsevier, Wiley Online library, China National Knowledge Infrastructure, WanFang data and Chongqing VIP. Effect sizes of odds ratio (OR) and 95% confidence interval (95%CI) were calculated by using a fixed- or random-effect model. Twelve case-control studies including 6141 cases and 7398 controls were selected. Significant differences in the distributions of allele frequency with CRC risk were directly present in ADIPOQ variants rs2241766, rs1501299 and ADIPOR variant rs1342387. In stratified analysis for different populations, significant differences were present in ADIPOQ variant rs822396 for Ashkenazi Jewish, in ADIPOQ variant rs1501299 and ADIPOR variant rs1342387 for Chinese and in ADIPOQ variant rs 2241766 for Ashkenazi Jewish and Chinese. In addition, the factors correlated with insulin resistance had synergistic effect with ADIPOQ variants rs2241766 T/G and rs1501299 G/T on risk of CRC. ADIPOQ variants rs2241766 T/G, rs1501299 G/T and ADIPOR variant ADIPOR rs1342387 G/A had a population specific correlation with CRC risk, which may be mediated by insulin resistance. And large well-designed studies are still needed for further evaluation of rs822396 and rs1063538, especially for their interaction and combined effect in the correlation with CRC risk.

A population-specific correlation between ADIPOQ rs2241766 and rs 1501299 and colorectal cancer risk: a meta-analysis for debate

AIMS

Many epidemiological studies have investigated the correlation between adiponectin, C1Q and collagen domain containing (ADIPOQ) single nucleotide polymorphisms (SNPs) and risk of colorectal cancer (CRC). Although conflicting results have been reported, there was dispute regarding two SNPs (rs2241766 T/G and rs1501299 G/T). Therefore, we conducted a meta-analysis to systematically assess the associations and try to find the reasons for the dispute.

METHODS

We searched PubMed, the Cochrane Library, Elsevier, Wiley Online Library, China National Knowledge Infrastructure, WanFang data and Chongqing VIP to search for all eligible case-control studies published up to January 2015. Effect sizes of odds ratios (OR) and 95 % confidence intervals (95 % CI) were calculated using a fixed- or random-effect model.

RESULTS

Ten case-control studies including 4377 cases and 5584 controls were selected. A significant difference was observed in Chinese (OR 0.76; 95 % CI 0.68, 0.85; P < 0.001) and Ashkenazi Jewish populations (OR 0.79; 95 % CI 0.63, 0.99; P = 0.04) for rs2241766 with dominant model (TT vs TG + GG). A significant difference was observed in the Chinese population (OR 1.23; 95 % CI 1.11, 1.37; P < 0.001) for rs1501299 with dominant model (TT vs TG + GG). In addition, intake of red meat showed a synergistic effect between ADIPOQ gene and risk of colorectal cancer (CRC).

CONCLUSIONS

ADIPOQ SNPs rs2241766 T/G and rs 1501299 G/T have a population-specific correlation with risk of CRC. However, small sample studies may increase reporting bias, particularly if the total number of studies included in the analysis is small.

Genetic Variations in Leptin and Leptin Receptor and Susceptibility to Colorectal Cancer and Obesity

Background

Colorectal cancer (CRC) is the second most commonly diagnosed cancer and the fourth leading cause of cancer-related mortality around the world.

Objectives

With regard to the role of obesity in colorectal cancer (CRC) and the role of leptin in obesity, we investigated whether leptin (LEP) and leptin receptor (LEPR) gene variants are associated with CRC risk.

Patients and Methods

We evaluated LEP (rs7799039) and LEPR (rs1137101) gene variants by using PCR-RFLP method in 261 cases with CRC and 339 controls.

Results

No significant difference was found for rs7799039 and rs1137101gene variants between the cases with CRC and controls. However, the LEPR rs1137101 “GG” genotype compared with “AA” genotype and “AA + AG” genotype was associated with increased risks for obesity, and the differences remained significant after adjustment for confounding factors including age, sex, smoking status, and NSAID use (P = 0.015; OR = 2.42, 95%CI = 1.19 - 4.93 and P = 0.016; OR = 2.28, 95%CI = 1.17 - 4.48, respectively). In addition, the LEPR “G” allele compared with the “A” allele was associated with an increased risk for obesity (P = 0.024; OR = 1.44, 95%CI = 1.05 - 1.98).

Conclusions

Consistent with most previous studies, our findings found no association between LEP (rs7799039) and LEPR (rs1137101) gene variants and CRC risk. However, the LEPR rs1137101 “GG” genotype compared with the “AA” genotype and “AA+AG” genotype was associated with a 2.42-fold and a 2.28-fold increased risk for obesity, respectively.

Gly972Arg variant of insulin receptor substrate 1 gene and colorectal cancer risk in overweight/obese subjects

BACKGROUND

Given the major role of obesity and insulin resistance (IR) in colorectal cancer (CRC), we investigated whether genetic variants in ghrelin (GHRL), resistin (RETN) and insulin receptor substrate 1 (IRS1) were associated with CRC risk.

METHODS

This study was conducted as a case-control study, and 750 subjects, including 438 controls and 312 patients with CRC, were enrolled and genotyped using the PCR-RFLP method.

RESULTS

No significant differences were observed for GHRL (rs696217), RETN (rs3745367) and IRS1 (rs1801278, Gly972Arg or G972R) gene variants between the cases and controls. However, the IRS1 G972R R allele compared with the G allele and the G972R RR+GR genotype compared with the GG genotype appeared to be markers of decreased CRC susceptibility in the overweight/obese subjects (p = 0.024; odds ratio [OR] = 0.42, 95% confidence interval [95% CI], 0.20-0.91; and p = 0.048; OR = 0.42, 95% CI, 0.17-0.99, respectively). Furthermore, the R allele and RR+GR genotype were also associated with decreased risks for obesity in the patients with CRC (p = 0.007; OR = 0.35, 95% CI, 0.15-0.77; and p = 0.015; OR = 0.35, 95% CI, 0.15-0.72, respectively).

CONCLUSIONS

In accordance with previous studies, our findings suggest that the IRS1 G972R R allele and RR+GR genotype have protective effects for CRC in overweight/obese patients and for obesity in patients with CRC. Nevertheless, further studies are required to confirm these findings.

Association between adiponectin polymorphisms and the risk of colorectal cancer

PURPOSE

To discuss the association between adiponectin (ADIPOQ) gene rs2241766 and rs1501299 polymorphisms and the risk of colorectal cancer, and to analyze the role of the interaction between these two loci and environmental factors in colorectal cancer pathogenesis.

METHODS

The case-control study was performed with a 1:1 match. A self-designed questionnaire was used to perform a face-to-face survey with 600 new primary colorectal cancer cases confirmed by histopathology as well as 600 cases of people receiving a physical examination at the same time. The general information, lifestyle, and diet habits, etc. were collected from two groups of study subjects. Polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) was used to identify ADIPOQ rs2241766 and rs1501299 genotypes.

RESULTS

After adjusting for factors such as colorectal cancer family history, body-mass index (BMI), daily sedentary time, weekly red meat intake frequency, as well regular tea drinking, conditional logistic regression analysis indicated that rs2241766 TG+GG carriers had a higher risk of colorectal cancer than TT carriers (OR=1.433, 95% CI: 1.014-1.985); rs1501299 GT+TT carriers had a lower risk of colorectal cancer than GG carriers (OR=0.723, 95% CI: 0.531-0.902). Generalized multifactor dimensionality reduction analysis showed that ADIPOQ rs2241766 and rs1501299 could have interaction with red meat intake (p=0.001).

CONCLUSION

ADIPOQ rs2241766 and rs1501299 single nucleotide polymorphisms (SNPs) could be associated with colorectal pathogenesis and could have interactions with red meat intake. Both factors impact colorectal cancer occurrence.

Associations between variants on ADIPOQ and ADIPOR1 with colorectal cancer risk: a Chinese case-control study and updated meta-analysis

Background

Epidemiological studies have suggested that variants on adiponectin (ADIPOQ) and its receptor ADIPOR1 (adiponectin receptor 1) are associated with colorectal cancer (CRC) risk; however, the results were inconclusive. The aim of the study was to evaluate the associations between the variants on ADIPOQ and ADIPOR1 and the CRC risk with a hospital-based case-control study in the Chinese population along with meta-analysis of available epidemiological studies.

Methods

With a hospital-based case-control study of 341 cases and 727 controls, the associations between the common variants on ADIPOQ (rs266729, rs822395, rs2241766 and rs1501299) and ADIPOR1 (rs1342387 and rs12733285) and CRC susceptibility were evaluated. Meta-analysis of the published epidemiological studies was performed to investigate the associations between the variants and CRC risk.

Results

For the population study, we found that variant rs1342387 of ADIPOR1 was associated with a reduced risk for CRC [adjusted odds ratio (OR) = 0.74, 95% confidential intervals (95% CI) = 0.57-0.97; CT/TT vs. CC]. The meta-analysis also suggested a significant association for rs1342387 and CRC risk; the pooled OR was 0.79 (95% CI = 0.66-0.95) for the CT/TT carriers compared to CC homozygotes under the random-effects model (Q = 8.06, df = 4, P = 0.089; I² = 50.4%). The case-control study found no significant association for variants rs266729, rs822395, rs2241766, and rs1501299 on ADIPOQ or variant rs12733285 on ADIPOR1 and CRC susceptibility, which were consistent with results from the meta-analysis studies.

Conclusions

These data suggested that variant rs1342387 on ADIPOR1 may be a novel CRC susceptibility factor.

Electronic supplementary material

The online version of this article (doi:10.1186/s12881-014-0137-y) contains supplementary material, which is available to authorized users.

Single nucleotide polymorphisms within interferon signaling pathway genes are associated with colorectal cancer susceptibility and survival

Interferon (IFN) signaling has been suggested to play an important role in colorectal carcinogenesis. Our study aimed to examine potentially functional genetic variants in interferon regulatory factor 3 (IRF3), IRF5, IRF7, type I and type II IFN and their receptor genes with respect to colorectal cancer (CRC) risk and clinical outcome. Altogether 74 single nucleotide polymorphisms (SNPs) were covered by the 34 SNPs genotyped in a hospital-based case-control study of 1327 CRC cases and 758 healthy controls from the Czech Republic. We also analyzed these SNPs in relation to overall survival and event-free survival in a subgroup of 483 patients. Seven SNPs in IFNA1, IFNA13, IFNA21, IFNK, IFNAR1 and IFNGR1 were associated with CRC risk. After multiple testing correction, the associations with the SNPs rs2856968 (IFNAR1) and rs2234711 (IFNGR1) remained formally significant (P = 0.0015 and P<0.0001, respectively). Multivariable survival analyses showed that the SNP rs6475526 (IFNA7/IFNA14) was associated with overall survival of the patients (P = 0.041 and event-free survival among patients without distant metastasis at the time of diagnosis, P = 0.034). The hazard ratios (HRs) for rs6475526 remained statistically significant even after adjustment for age, gender, grade and stage (P = 0.029 and P = 0.036, respectively), suggesting that rs6475526 is an independent prognostic marker for CRC. Our data suggest that genetic variation in the IFN signaling pathway genes may play a role in the etiology and survival of CRC and further studies are warranted.

Resistin -420C>G promoter variant and colorectal cancer risk

PURPOSES

Obesity is associated with an increased risk of colorectal cancer (CRC), and ghrelin (GHRL) and resistin (RETN) are thought to be related to obesity. Our aim was to investigate whether GHRL and RETN gene variants are associated with CRC risk.

MATERIALS AND METHODS

All 414 subjects, including 197 cases with CRC and 217 controls, were genotyped for the GHRL (rs26802) and RETN (rs1862513) or -420 C>G gene variants using the PCR-RFLP method.

RESULTS

Our findings indicated that the RETN -420 C>G "CC" genotype, compared with the "GG" and "GC" genotypes, was a marker of decreased CRC susceptibility; the difference remained significant after adjustment for age, BMI, gender, smoking status, NSAID use, and family history of CRC (p=0.020; OR=0.52, 95% CI=0.30-0.90). Furthermore, after adjustment for confounding factors, the -420 C>G "CC" genotype, compared with the "GG" genotype, was associated with a decreased risk for CRC (p=0.044; OR=0.53, 95% CI=0.29-0.98). In addition, no significant difference was observed for the GHRL (rs26802) gene variant.

CONCLUSIONS

To our knowledge, this is the first study suggesting that the RETN -420 C>G "CC" genotype is a marker of decreased CRC susceptibility. This observation is relevant from a scientific perspective and deserves further investigations.

Mechanisms behind the link between obesity and gastrointestinal cancers

Obesity and obesity-related disorders such as non-alcoholic fatty liver disease (NAFLD), metabolic syndrome and type 2 diabetes exhibit an increased risk of developing various gastrointestinal cancers. These malignancies include mainly esophageal, gastric, colorectal, pancreatic and hepatocellular carcinoma. Whereas underlying pathomechanisms remain unclear, chronic inflammation accompanying obesity has evolved in the last years as a crucial contributing factor. Obesity is also commonly characterized by inflammation in the organ where those cancers appear. Various pathways might participate involving rather diverse components such as innate immunity, (adipo)-cytokines such as adiponectin or leptin, insulin, insulin-like growth factors, the gut's microbiota and others. An imbalance in these systems could substantially contribute to chronic inflammation and subsequent cancer development. Future studies have to elucidate in more detail underlying mechanisms in the development of obesity-related carcinogensis and potential therapeutic strategies besides weight loss.

Resistin as a biomarker linking obesity and inflammation to cancer: potential clinical perspectives

Excess body weight is associated with various types of malignancies. Resistin, originally described as an adipocyte-specific hormone modulating insulin resistance in rodents, may exhibit proliferative, antiapoptotic, proinflammatory, proangiogenic and metastatic properties. Accumulating evidence supports a role of resistin as a risk factor and potential diagnostic and prognostic biomarker in cancer. In this report, the current knowledge about resistin's properties and pathophysiological implications in cancer in the context of dysregulated adipose tissue in obesity is summarized; clinical translations, preventive and therapeutic considerations, and future perspectives in the field of resistin research are discussed. At the same time, several enigmatic issues involving resistin receptor and signaling pathways remain to be clarified in order to unmask its ontological role in cancer pathophysiology.

Polymorphisms in RETN gene and susceptibility to colon cancer in Saudi patients

BACKGROUND AND OBJECTIVES

Resistin is an adipocytokine, which has been studied for its role in insulin resistance and recently in inflammation. Several single-nucleotide polymorphisms (SNPs) have been identified in the human resistin gene (RETN). This study aims to investigate the association of RETN rs1862513 (C-420G) and rs3745367 (G+299A) SNPs with the colon cancer risk in Saudi patients.

DESIGN AND SETTING

This is a case-control study conducted among Saudi adult colon cancer patients recruited from King Abdulaziz Hospital and Oncology Center in Jeddah, Saudi Arabia.

SUBJECTS AND METHODS

In this study, 120 Saudi volunteers (60 colon cancer patients and 60 disease-free controls) were studied. The SNPs were determined by polymerase chain reaction (PCR) and genotyping using PCR- restriction fragment length polymorphism analysis.

RESULTS

In comparing the result obtained for the patient group with that of the controls, colon cancer group displayed different genotype distribution of the RETN C-420G and G+299A SNPs. The study indicated that the SNP-420 heterozygous (CG) genotype (odds ratio [OR]=2.48, 95% CI 1.07-5.74, P=.03) and the SNP +299 heterozygous (GA) genotype (OR=6.5, 95% CI 1.77-24.18, P=.002) significantly increased the risk of colon cancer. A further analysis of the genotype combination of SNPs RETN C-420G and G+299A showed a larger increase in the colon cancer risk.

CONCLUSION

These preliminary results suggested a potential role for RETN C-420G and G+299A polymorphisms in the genetic predisposition to colon cancer disease.

Five common haplotype-tagging variants of adiponectin (ADIPOQ) and cancer susceptibility: a meta-analysis

AIMS

The relationship between common haplotype-tagging polymorphisms (rs266729 [11365C>G], rs822395 [-4034A>C], rs822396 [-3964A>G], rs2241766 [45T>G], and rs1501299 [276G>T]) in the ADIPOQ gene and cancer risk has been investigated in different ethnic groups; however, these studies have yielded contradictory results. With this in mind, this meta-analysis was performed in an attempt to draw a more precise conclusion regarding the association between ADIPOQ polymorphisms and cancer risk.

RESULTS

In this study, with a total of 19 eligible articles consisting of 52 studies, the pooled odds ratios (ORs) for the association between ADIPOQ rs1501299 and cancer risk were statistically significant (dominant model, TT/GT vs. GG, OR=0.84, 95% confidence interval [CI]: 0.77-0.92; homozygous model, TT vs. GG, OR=0.80, 95% CI: 0.68-0.94). These results suggested that ADIPOQ rs1501299 might be a protection-associated polymorphism in cancer. The stratified analyses indicated that the variant T allele of ADIPOQ rs1501299 was associated with decreased risk of cancer in both Caucasian and Asian populations when compared with the G allele. No significant association for the rest of the polymorphisms was observed under any genetic model.

CONCLUSIONS

This meta-analysis suggests that the ADIPOQ rs1501299 may be a protective factor for carcinogenesis.

An updated meta-analysis of the association between ADIPOQ rs2241766 polymorphism and colorectal cancer

Adiponectin (ADIPOQ) is a cytokine produced by adipose tissue involved in carcinogenesis. ADIPOQ SNP rs2241766 has been extensively studied in colorectal cancer (CRC) community with contentious and conflicting conclusions. The objective of this study was to comprehensively assess the association between SNP rs2241766 and CRC risk. PubMed, Embase, CNKI, as well as the references of the retrieved articles were searched to identify the eligible studies for this meta-analysis. Odds ratios (ORs) and 95 % confidence intervals (CIs) were used to assess the association. We also examined the heterogeneity and publication bias and performed sensitivity analyses. Seven studies with 2,414 cases and 2,796 controls together did not show any significant association between SNP rs2241766 and CRC risk. Subgroup analyses by ethnicity and sample size also failed to provide statistically significant evidence. This meta-analysis demonstrates that ADIPOQ SNP rs2241766 may not represent as an effect modifier for the risk of CRC.

Association between adiponectin gene polymorphisms and risk of colorectal cancer: A Meta-analysis

AIM: To investigate the association between adiponectin (ADIPOQ) gene polymorphisms and risk of colorectal cancer (CRC).

METHODS: All eligible case-control studies published up to March 2013 were identified by searching PubMed, Web of Science, CNKI, Wanfang and VIP. Effect sizes of odds ratio (OR) and 95% confidence interval (95%CI) were calculated by using a fixed- or random-effect model.

RESULTS: A total of 9 case-control studies were included. There were eight studies (2024 cases and 2777 controls) for rs1501299G/T polymorphism, five studies (1401 cases and 1691 controls) for rs2241766T/G polymorphism and five studies (2945 cases and 3361 controls) for rs266729C/G polymorphism. Overall, a significant association was observed for rs2241766T/G polymorphism under heterozygote comparison (TG vs TT: OR = 1.22, 95%CI: 1.05-1.43), while there was no significant association for rs2241766 polymorphism under other genetic models, and for other two polymorphisms under all genetic models.

CONCLUSION: Our meta-analysis indicates that adiponectin rs2241766T/G polymorphism, rather than rs1501299G/T and rs266729C/G polymorphisms, is associated with the risk of colorectal cancer.

Plasma adiponectin and soluble leptin receptor and risk of colorectal cancer: a prospective study

Adipokines are adipocyte-secreted hormones that may mediate the etiologic link between obesity and colorectal cancer; however, the evidence from large prospective studies is limited. We prospectively evaluated the association of plasma adiponectin and soluble leptin receptor (sOB-R) with colorectal cancer risk within the Nurses' Health Study (1990-2008) and the Health Professionals Follow-up Study (1994-2008) among 616 incident colorectal cancer cases and 1,205 controls selected using risk-set sampling and matched on age and date of blood draw. In unconditional logistic regression with adjustment for matching factors and multiple risk factors, plasma adiponectin was significantly associated with reduced risk of colorectal cancer among men, but not among women. Compared with men in the lowest quartile of adiponectin, men in the highest quartile had a relative risk (RR) for colorectal cancer of 0.55 [95% confidence interval (CI), 0.35-0.86; Ptrend = 0.02]. The corresponding RR in women was 0.96 (95% CI, 0.67-1.39; Ptrend = 0.74). Plasma sOB-R was not associated with overall colorectal cancer risk in either men or women. A significant heterogeneity was noted in the association between sOB-R and colorectal cancer by subsite in women (Pheterogeneity = 0.004); sOB-R was significantly associated with increased risk of rectal cancer but not colon cancer. These findings support a role for adiponectin in colorectal carcinogenesis in men. Further studies are warranted to confirm these associations and elucidate potential underlying mechanisms.

LEP gene variant is associated with prostate cancer but not with colorectal cancer

The leptin (LEP) gene has been considered to be implicated in the development of cancer. However, the results have been inconsistent. In this study, we performed a meta-analysis to clarify the association of LEP rs7799039 variant with colorectal and prostate cancer risk. Published literatures from PubMed and Embase were retrieved. Pooled odds ratio (OR) with 95 % confidence interval (CI) was calculated using fixed or random effects model. A total of five studies (2,596 colorectal cancer cases and 3,240 controls) for association of LEP rs7799039 variant with colorectal cancer, and three studies (1,343 prostate cancer cases and 1,238 controls) for association with prostate cancer were included in the meta-analysis. For colorectal cancer, there was no significant association of LEP rs7799039 variant with this disease under homogeneous co-dominant model (OR = 0.88, 95 % CI = 0.75-1.02), heterogeneous co-dominant model (OR = 1.00, 95 % CI = 0.89-1.13) and dominant model (OR = 0.97, 95 % CI = 0.87-1.08); however, there was a marginal association under recessive model (OR = 0.87, 95 % CI = 0.76-0.99). For prostate cancer, there was significant association of LEP rs7799039 variant with this disease under homogeneous co-dominant model (OR = 1.33, 95 % CI = 1.06-1.67) and recessive model (OR = 1.26, 95 % CI = 1.05-1.51), but not under heterogeneous co-dominant model (OR = 1.24, 95 % CI = 0.87-1.77) and dominant model (OR = 1.30, 95 % CI = 1.84). The present meta-analysis demonstrated that the LEP rs7799039 variant was associated with prostate cancer, but not with colorectal cancer.

Genetic variants in C-type lectin genes are associated with colorectal cancer susceptibility and clinical outcome

Inflammatory responses play a vital role at different stages of colorectal carcinogenesis. C-type lectins mediate inflammatory/immune responses and participate in immune escape of pathogens and tumors. Our study aimed to evaluate the correlation between polymorphisms in three C-type lectin genes, CD209, MBL2 and REG4, and colorectal cancer (CRC) risk and clinical outcome. We genotyped 15 potentially functional single nucleotide polymorphisms (SNPs) and assessed their associations with CRC risk in a case-control study of 1353 CRC cases and 767 healthy controls from the Czech Republic. We also analyzed these SNPs in relation to overall and event-free survival in 414 patients. Two CD209 SNPs were associated with CRC risk after adjustment for multiple comparison. Minor allele carriers of the promoter SNP rs2287886 had an increased risk of CRC (OR 1.30, 95% CI 1.08-1.56), while minor allele carriers of the 3'UTR SNP, rs7248637, had a decreased risk (OR 0.74, 95% CI 0.60-0.91). Multivariate survival analyses, including age, gender, TNM stage and grade, showed that patients without distant metastasis at the time of diagnosis and carrying the rs2994809 T allele had a decreased overall and event-free survival (HR 2.11, 95% CI 1.20-3.72 and HR 2.00, 95% CI 1.18-3.39, respectively). We show that SNPs in CD209 may affect CRC risk, while a SNP in REG4 may be a useful marker for CRC progression.

Role of leptin receptor (LEPR) gene polymorphisms and haplotypes in susceptibility to hepatocellular carcinoma in subjects with chronic hepatitis B virus infection

AIM

The reported association of the leptin receptor (LEPR) protein with hepatocellular carcinoma (HCC) carcinogenesis prompted us to evaluate whether genetic polymorphisms of the LEPR gene affect susceptibility to HCC and its clinicopathologic characteristics.

METHODS

A total of 417 subjects who were diagnosed with HCC and 551 age- and sex-matched subjects without HCC were enrolled in this study. All subjects had chronic hepatitis B virus (HBV) infection. Three single nucleotide polymorphisms (SNPs) of the LEPR gene were determined.

RESULTS

The genotype frequencies of Lys109Arg and Gln223Arg differed significantly between HCC and non-HCC subjects (both p < 0.001). For the Lys109Arg polymorphism, HCC subjects had a higher prevalence of 109Arg/Arg than non-HCC subjects. The 109Arg/Arg carriers had a significantly higher adjusted risk of HCC than the 109Lys/Lys carriers. For the Gln223Arg polymorphism, subjects with the 223Arg/Arg genotype had a significantly higher risk of HCC than those with the 223Gln/Gln genotype. The Lys656Asn SNP did not affect the HCC risk. Haplotype analyses showed that subjects with 109Lys-656Lys-223Arg and 109Arg-656Asn-223Arg haplotypes had an increased HCC risk, while the 109Lys-656Lys-223Gln and 109Lys-656Asn-223Gln haplotypes had protective effects against HCC development. None of these polymorphisms were related to the clinicopathologic features of HCC.

CONCLUSION

The Lys109Arg and Gln223Arg polymorphisms of the LEPR gene are associated with susceptibility to HCC but not with its clinicopathologic features. These polymorphisms may represent genetic markers for the risk of HCC in the context of chronic HBV infection.

Changes in serum IGF-1 level and tumor VEGF expression in mice with colorectal cancer under hyperglycemic conditions

The present study aimed to observe the growth of transplanted tumors in mice with colorectal cancer (CRC) under hyperglycemic conditions and to detect the expression of vascular endothelial growth factor (VEGF) in these tumors. The study also aimed to observe the changes in serum insulin-like growth factor-1 (IGF-1) levels and to determine whether type 2 diabetes mellitus (T2DM) was a risk factor for the progression and development of CRC. A mouse model of a transplanted colorectal tumor with T2DM was established to observe the changes in volume and size of the transplanted tumor. Mice were sacrificed at the end of the 5th week to determine the serum IGF-1 level and VEGF expression in the tumor tissues. The tumor volume (1628.5 ± 882 mm3) in the CRC-DM group was larger than that in the CRC group (1950.2 ± 726 mm3; P<0.05). The serum IGF-1 level (105.33 ± 32.32 ng/ml) was higher than that in the normal (69.83 ± 25.57 ng/ml) and CRC groups (70.17 ± 25.27 ng/ml; P<0.05). The VEGF expression in the tumor tissues of the CRC-DM group(70.0 ± 11.5%) was higher than that in the CRC group (42.9 ± 7.5%; P<0.05). T2DM may be one of the causes for the promotion of CRC growth and its mechanism may be correlated with the increased IGF-1 action observed in the blood that induces VEGF gene transcription, upregulates VEGF expression, causes tumor angiogenesis and thus leads to the occurrence and metastasis of tumors.

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.

Association between prediagnostic biomarkers of inflammation and endothelial function and cancer risk: a nested case-control study

Experimental and prevalent case-control studies suggest an association between biomarkers of inflammation, endothelial function, and adiposity and cancer risk, but results from prospective studies have been limited. The authors' objective was to prospectively examine the relations between these biomarkers and cancer risk. A nested case-control study was designed within the Supplémentation en Vitamines et Minéraux Antioxydants (SU.VI.MAX) Study, a nationwide French cohort study, to include all first primary incident cancers diagnosed between 1994 and 2007 (n = 512). Cases were matched with randomly selected controls (n = 1,024) on sex, age (in 2-year strata), body mass index (weight (kg)/height (m)(2); <25 vs. ≥25), and SU.VI.MAX intervention group. Conditional logistic regression was used to study the associations between prediagnostic levels of high-sensitivity C-reactive protein (hs-CRP), adiponectin, leptin, soluble intercellular adhesion molecule 1 (sICAM-1), soluble vascular cell adhesion molecule 1, soluble E-selectin, and monocyte chemoattractant protein 1 and cancer risk. All statistical tests were 2-sided. Plasma sICAM-1 level was positively associated with breast cancer risk (for quartile 4 vs. quartile 1, multivariate odds ratio (OR) = 1.86, 95% confidence interval (CI): 1.06, 3.26; P(trend) = 0.048). Plasma hs-CRP level was positively associated with prostate cancer risk (for quartile 4 vs. quartile 1, multivariate OR = 3.04, 95% CI: 1.28, 7.23; P(trend) = 0.03). These results suggest that prediagnostic hs-CRP and sICAM-1 levels are associated with increased prostate and breast cancer risk, respectively.

Meta-analysis of adiponectin polymorphisms and colorectal cancer risk

OBJECTIVE

The adiponectin gene (ADIPOQ) has been suggested to be associated with the pathogenesis of colorectal cancer (CRC). However, the results have been inconsistent. In this study, we performed a meta-analysis to investigate the association between adiponectin polymorphisms and CRC risk.

METHODS

All eligible case-control studies published up to March 2013 were identified by searching PubMed, Web of Science and CNKI. Effect sizes of odds ratio (OR) and 95% confidence interval (95% CI) were calculated by using a fixed- or random-effect model.

RESULTS

A total of 9 case-control studies were included, Of those studies, there were eight studies (2024 cases and 2777 controls) for rs1501299G/T polymorphism, five studies (1401 cases and 1691 controls) for rs2241766T/G polymorphism, five studies (2945 cases and 3361 controls) for rs266729C/G polymorphism, three studies (1221 cases and 1579 controls) for rs822395A/C polymorphism and three studies (1222 cases and 1575 controls) for rs822396A/G polymorphism. Overall, a significant association was observed for rs2241766T/G polymorphism under heterozygote comparison (TG vs. TT: OR=1.22, 95%CI: 1.05-1.43); while there was no significant association for rs2241766 polymorphism under other genetic models, and for other four polymorphisms under all genetic models. Besides, when stratified analyses by ethnicity, no significant association between five polymorphisms and CRC risk were observed under all genetic models among Asian, Caucasian and African-American.

CONCLUSIONS

This meta-analysis indicated that adiponectin rs2241766T/G rather than rs1501299G/T, rs266729C/G, rs822395A/C and rs822396A/G polymorphism was associated with the risk of colorectal cancer.

Adiponectin (ADIPOQ) rs2241766 G/T polymorphism is associated with risk of cancer: evidence from a meta-analysis

Associations between adiponectin (ADIPOQ) genetic polymorphisms (rs2241766 G/T and rs266729 G/C) and cancer risk have been extensively studied in the past decade, while conflicting results were reported. Therefore, this study would explore the associations by using a meta-analysis. The databases of Medline, Embase, and Wangfang were retrieved, and the latest updated time was 1 August 2012. Effect sizes of odds ratio and 95 % confidence interval (OR and 95 % CI) were calculated by using a fixed- or random-effect model. A total of 12 studies with 10,368 participants were identified for association between ADIPOQ rs2241766 G/T and risk of cancer, and ten studies with 12,665 participants were for association between ADIPOQ rs266729 G/C and risk of cancer. Overall combined analyses indicated that neither ADIPOQ rs2241766 G/T nor rs266729 G/C was associated with risk of cancer incidence (OR (95 % CI), 0.89 (0.61-1.30) for GG vs. TT and 0.94 (0.83-1.06) for G carriers vs. T carriers for rs2241766 G/T; 0.99 (0.85-1.16) for GG vs. CC and 0.96 (0.87-1.06) for G carriers vs. C carriers for rs266729 G/C). When stratified analyses were conducted according to the participants' ethnicity, sources of controls, types of cancer, and sample size, we found that G allele of ADIPOQ rs2241766 G/T was significantly associated with decreased risk of cancer based on population-based case-control studies (OR (95 % CI), 0.65 (0.50-0.85) for GG vs. TT and 0.88 (0.79-0.98) for G carriers vs. T carriers). In contrast, there was no association between rs266729 G/C polymorphism and risk of cancer when subgroup analyses were conducted. In summary, this meta-analysis indicated that ADIPOQ rs2241766 G/T rather than rs266729 G/C polymorphism was closely associated with risk of cancer development.

The roles of ADIPOQ genetic variations in cancer risk: evidence from published studies

Adiponectin produced by adipose tissue, which is involved in complex diseases related to obesity, such as cancer. Genetic variations in ADIPOQ are thought to influence the activity of adiponectin, thus relating to cancer occurrence. However, epidemiological results were inconsistent. To examine this controversy, we assessed reported studies of association between ADIPOQ polymorphisms and cancer risk. Relevant studies were selected by PUBMED, EMBASE update to January 12th, 2012. According to the acceptance and exclusion criteria, 15 studies involved three polymorphisms (rs266729, rs2241766, rs1501299) of ADIPOQ were included. Summary odds ratio (ORs) and 95 % confidence intervals (CIs) were calculated using random-effect or fixed-effect models based on the heterogeneity of included studies. A total of 15 case-control studies related rs266729 (5,615 cases and 6,425 controls), rs2241766 (5,318 cases and 6,118 controls) and rs1501299 (3,751 cases and 5,104 controls) were included to analyze the ADIPOQ polymorphisms and cancer risk. For rs1501299, T allele was associated with decreased cancer risk. In addition, cancer type subgroup analysis revealed T allele was associated with decreased colorectal and prostate cancer risk. Ethnicity subgroup analysis observed a decreased risk in both Asian and Caucasian descendents. As to rs2241766, a borderline decreased cancer risk was observed. This meta-analysis indicated T allele of rs1501299 was an obvious protection factor for cancer risk, and G allele of rs2241766 was a potential protection factor for cancer risk, especially in Caucasian descendents. Further studies should be performed to clarify the roles of ADIPOQ polymorphisms in the cancer risk.

Shared ancestral susceptibility to colorectal cancer and other nutrition related diseases

Background

The majority of non-syndromic colorectal cancers (CRCs) can be described as a complex disease. A two-stage case–control study on CRC susceptibility was conducted to assess the influence of the ancestral alleles in the polymorphisms previously associated with nutrition-related complex diseases.

Methods

In stage I, 28 single nucleotide polymorphisms (SNPs) were genotyped in a hospital-based Czech population (1025 CRC cases, 787 controls) using an allele-specific PCR-based genotyping system (KASPar®). In stage II, replication was carried out for the five SNPs with the lowest p values. The replication set consisted of 1798 CRC cases and 1810 controls from a population-based German study (DACHS). Odds ratios (ORs) and 95% confidence intervals (CIs) for associations between genotypes and CRC risk were estimated using logistic regression. To identify signatures of selection, Fay-Wu’s H and Integrated Haplotype Score (iHS) were estimated.

Results

In the Czech population, carriers of the ancestral alleles of AGT rs699 and CYP3A7 rs10211 showed an increased risk of CRC (OR 1.26 and 1.38, respectively; two-sided p≤0.05), whereas carriers of the ancestral allele of ENPP1 rs1044498 had a decreased risk (OR 0.79; p≤0.05). For rs1044498, the strongest association was detected in the Czech male subpopulation (OR 0.61; p=0.0015). The associations were not replicated in the German population. Signatures of selection were found for all three analyzed genes.

Conclusions

Our study showed evidence of association for the ancestral alleles of polymorphisms in AGT and CYP3A7 and for the derived allele of a polymorphism in ENPP1 with an increased risk of CRC in Czechs, but not in Germans. The ancestral alleles of these SNPs have previously been associated with nutrition-related diseases hypertension (AGT and CYP3A7) and insulin resistance (ENPP1). Future studies may shed light on the complex genetic and environmental interactions between different types of nutrition-related diseases.

Genetic association of adiponectin with type 2 diabetes in Jordanian Arab population

Adiponectin, a protein exclusively secreted by adipose tissue and present at low levels in obese individuals, is now widely recognized as a key determinant of insulin sensitivity and protection against obesity-associated metabolic syndrome. In Jordan, prevalence of diabetes (17.1%) is twice that of the United States (7.8%). In this study, we examined the contribution of the promoter variant rs266729 (-11377C>G) of the ADIPOQ gene as a risk factor for diabetic patients in Jordan. DNA was extracted from blood samples for patients and controls .Polymerase chain reaction and restriction fragment length polymorphism were used to genotype this variant. A total of 420 type 2 diabetic patients and 230 controls were successfully genotyped. The results showed a significant genotypic (p=0.00001) and allelic (p=0.01) association with variant in the diabetic patients as compared to controls. This suggests that the ADIPOQ gene plays a major role in increasing the risk of diabetes, at least in the Jordanian Arab population.

An integrated approach to identify causal network modules of complex diseases with application to colorectal cancer

BACKGROUND

Many methods have been developed to identify disease genes and further module biomarkers of complex diseases based on gene expression data. It is generally difficult to distinguish whether the variations in gene expression are causative or merely the effect of a disease. The limitation of relying on gene expression data alone highlights the need to develop new approaches that can explore various data to reflect the casual relationship between network modules and disease traits.

METHODS

In this work, we developed a novel network-based approach to identify putative causal module biomarkers of complex diseases by integrating heterogeneous information, for example, epigenomic data, gene expression data, and protein-protein interaction network. We first formulated the identification of modules as a mathematical programming problem, which can be solved efficiently and effectively in an accurate manner. Then, we applied our approach to colorectal cancer (CRC) and identified several network modules that can serve as potential module biomarkers for characterizing CRC. Further validations using three additional gene expression datasets verified their candidate biomarker properties and the effectiveness of the method. Functional enrichment analysis also revealed that the identified modules are strongly related to hallmarks of cancer, and the enriched functions, such as inflammatory response, receptor and signaling pathways, are specific to CRC.

RESULTS

Through constructing a transcription factor (TF)-module network, we found that aberrant DNA methylation of genes encoding TF considerably contributes to the activity change of some genes, which may function as causal genes of CRC, and that can also be exploited to develop efficient therapies or effective drugs.

CONCLUSION

Our method can potentially be extended to the study of other complex diseases and the multiclassification problem.

The role of adiponectin in cancer: a review of current evidence

Excess body weight is associated not only with an increased risk of type 2 diabetes and cardiovascular disease (CVD) but also with various types of malignancies. Adiponectin, the most abundant protein secreted by adipose tissue, exhibits insulin-sensitizing, antiinflammatory, antiatherogenic, proapoptotic, and antiproliferative properties. Circulating adiponectin levels, which are determined predominantly by genetic factors, diet, physical activity, and abdominal adiposity, are decreased in patients with diabetes, CVD, and several obesity-associated cancers. Also, adiponectin levels are inversely associated with the risk of developing diabetes, CVD, and several malignancies later in life. Many cancer cell lines express adiponectin receptors, and adiponectin in vitro limits cell proliferation and induces apoptosis. Recent in vitro studies demonstrate the antiangiogenic and tumor growth-limiting properties of adiponectin. Studies in both animals and humans have investigated adiponectin and adiponectin receptor regulation and expression in several cancers. Current evidence supports a role of adiponectin as a novel risk factor and potential diagnostic and prognostic biomarker in cancer. In addition, either adiponectin per se or medications that increase adiponectin levels or up-regulate signaling pathways downstream of adiponectin may prove to be useful anticancer agents. This review presents the role of adiponectin in carcinogenesis and cancer progression and examines the pathophysiological mechanisms that underlie the association between adiponectin and malignancy in the context of a dysfunctional adipose tissue in obesity. Understanding of these mechanisms may be important for the development of preventive and therapeutic strategies against obesity-associated malignancies.

Pre-diagnostic levels of adiponectin and soluble vascular cell adhesion molecule-1 are associated with colorectal cancer risk

AIM: To examine the relationships between pre-diagnostic biomarkers and colorectal cancer risk and assess their relevance in predictive models.

METHODS: A nested case-control study was designed to include all first primary incident colorectal cancer cases diagnosed between inclusion in the SUpplémentation en VItamines et Minéraux AntioXydants cohort in 1994 and the end of follow-up in 2007. Cases (n = 50) were matched with two randomly selected controls (n = 100). Conditional logistic regression models were used to investigate the associations between pre-diagnostic levels of hs-CRP, adiponectin, leptin, soluble vascular cell adhesion molecule-1 (sVCAM-1), soluble intercellular adhesion molecule-1, E-selectin, monocyte chemoattractant protein-1 and colorectal cancer risk. Area under the receiver operating curves (AUC) and relative integrated discrimination improvement (RIDI) statistics were used to assess the discriminatory potential of the models.

RESULTS: Plasma adiponectin level was associated with decreased colorectal cancer risk (P for linear trend = 0.03). Quartiles of sVCAM-1 were associated with increased colorectal cancer risk (P for linear trend = 0.02). No association was observed with any of the other biomarkers. Compared to standard models with known risk factors, those including both adiponectin and sVCAM-1 had substantially improved performance for colorectal cancer risk prediction (P for AUC improvement = 0.01, RIDI = 26.5%).

CONCLUSION: These results suggest that pre-diagnostic plasma adiponectin and sVCAM-1 levels are associated with decreased and increased colorectal cancer risk, respectively. These relationships must be confirmed in large validation studies.

Ancestral susceptibility to colorectal cancer

Every year, approximately 1 million new colorectal cancer (CRC) cases are diagnosed and about half a million people worldwide die due to this cancer. Known differences in CRC incidence rates are mainly attributed to differences in diet and other environmental factors represented, among others, by nutrition-related complex diseases (e.g. obesity and diabetes mellitus type II). Within the last years, it has become evident that environmental risk factors can be complemented by a genetic component when considering the risk of CRC. For example, a number of polymorphisms are known to be associated with an increased risk of obesity and obesity is a risk factor for CRC. Several studies have shown that the 'ancestral-susceptibility model' can be reasonably applied to nutrition-related complex diseases such as obesity. The work in hand shortly discusses whether the ancestral-susceptibility model can also be applied to CRC as a nutrition-related complex disease.

Total and high-molecular weight adiponectin and risk of colorectal cancer: the European Prospective Investigation into Cancer and Nutrition Study

Adiponectin-an adipose tissue-derived protein-may provide a molecular link between obesity and colorectal cancer (CRC), but evidence from large prospective studies is limited. In particular, no epidemiological study explored high-molecular weight (HMW) and non-HMW adiponectin fractions in relation to CRC risk, despite them being hypothesized to have differential biological activities, i.e. regulating insulin sensitivity (HMW adiponectin) versus inflammatory response (non-HMW adiponectin). In a prospective, nested case-control study, we investigated whether prediagnostic serum concentrations of total, HMW and non-HMW adiponectin are associated with risk of CRC, independent of obesity and other known CRC risk factors. A total of 1206 incident cases (755 colon and 451 rectal) were matched to 1206 controls using incidence-density sampling. In conditional logistic regression, adjusted for dietary and lifestyle factors, total adiponectin and non-HMW adiponectin concentrations were inversely associated with risk of CRC [relative risk (RR) comparing highest versus lowest quintile = 0.71, 95% confidence interval (CI) = 0.53-0.95, P(trend) = 0.03 for total adiponectin and RR = 0.45, 95% CI = 0.34-0.61, P(trend) < 0.0001 for non-HMW adiponectin]. HMW adiponectin concentrations were not associated with CRC risk (RR = 0.91, 95% CI = 0.68-1.22, P(trend) = 0.55). Non-HMW adiponectin was associated with CRC risk even after adjustment for body mass index and waist circumference (RR = 0.39, 95% CI = 0.26-0.60, P(trend) < 0.0001), whereas the association with total adiponectin was no longer significant (RR = 0.81, 95% CI = 0.60-1.09, P(trend) = 0.23). When stratified by cancer site, non-HMW adiponectin was inversely associated with both colon and rectal cancer. These findings suggest an important role of the relative proportion of non-HMW adiponectin in CRC pathogenesis. Future studies are warranted to confirm these results and to elucidate the underlying mechanisms.

The role of leptin receptor gene polymorphisms in determining the susceptibility and prognosis of NSCLC in Chinese patients

AIM

Although the role of genetic polymorphisms of leptin receptor (LEPR) gene in several cancers has been documented, the association between polymorphisms of LEPR gene and lung cancer remains unknown.

METHOD

We recruited 744 patients histologically diagnosed as non-small cell lung cancer (NSCLC) and 832 controls in this study. Polymorphism analysis of LEPR gene was performed by PCR-restriction fragment length polymorphisms.

RESULTS

The Arg/Arg genotype and Arg allele frequency of the Gln223Arg in LEPR gene were significantly prevalent in NSCLC subjects than in controls (P < 0.05). The odd ratio (OR) for NSCLC in Arg/Arg genotype carriers was 3.12 (95% CI: 2.25-4.56, P = 0.0023, with Gln/Gln as reference). There were no significant differences in the genotype distributions and allele frequencies of Lys109Arg and Lys656Asn in LEPR gene between NSCLC cases and controls (All P > 0.05). The Arg/Arg carriers had higher cancer grade and higher TNM stage. Kaplan-Mier curve showed the Arg/Arg carriers had a poor prognosis than those with Gln/Arg and Gln/Gln genotype carriers. Cox proportional hazards regression models showed the hazard ratio (HR) for death associated with Arg/Arg genotype was 3.43 (95% CI: 2.45-5.92, compared with Gln/Gln carriers, P = 0.002). The other two SNPs of LEPR gene did not show this trend in the evaluation of their role in determining the prognosis of NSCLC subjects.

CONCLUSION

The results suggest the polymorphisms of Gln223Arg, rather than Lys109Arg and Lys656Asn, may be used as a molecular marker for progression and prognosis of NSCLC.

Genetic polymorphisms in obesity-related genes and endometrial cancer risk

BACKGROUND

Obesity is associated with circulating levels of adiponectin and leptin and endometrial cancer risk. Little is known about whether single nucleotide polymorphisms (SNPs) in the genes that encode adiponectin (ADIPOQ), leptin (LEP), adiponectin receptor 1 (ADIPOR1), adiponectin receptor 2 (ADIPOR2), and leptin receptor (LEPR) are associated with endometrial cancer.

METHODS

The authors selected 87 tagging SNPs to capture common genetic variants in these 5 genes. These SNPs were evaluated in 1028 endometrial cancer cases and 1932 community controls recruited from Chinese women. Logistic regression models were used to estimate odds ratios (ORs) and 95% confidence intervals (95% CIs).

RESULTS

Three of the 10 SNPs evaluated in the ADIPOQ gene were significantly associated with reduced cancer risk. The OR for women homozygous for the minor allele (A/A) for rs3774262 was 0.68 (95% CI, 0.48-0.97) compared with women homozygous for the major allele (G/G). Similar results were found for SNPs rs1063539 and rs12629945 in ADIPOQ, which were in linkage disequilibrium with rs3774262. These associations became nonsignificant after Bonferroni correction was applied. Controls with the minor allele A at rs3774262 had lower weight, smaller waist and hip circumferences, and lower body mass index than controls with the major allele G (all P < .05). Women homozygous for the minor allele (T/T) of rs2071045 in the LEP gene also had significantly lower risk (OR, 0.70; 95% CI, 0.54-0.90) than women homozygous for the major allele (C/C). No other SNPs in the LEP, ADIPOR1, ADIPOR2, or LEPR genes were found to be associated with cancer risk.

CONCLUSIONS

Although a chance finding cannot be ruled out, the consistency of findings for gene-endometrial cancer risk and gene-obesity measurements suggests that genetic polymorphisms in the ADIPOQ gene may play a role in endometrial cancer development.

Adiponectin gene and risk of colorectal cancer

Background:

Genes of the adiponectin pathway are interesting candidates for colorectal cancer risk based on the potential association between colorectal cancer and obesity. However, variants of the adiponectin gene (ADIPOQ) have been demonstrated to be inconsistently associated with risk of colorectal cancer.

Methods:

The current study attempted to evaluate these findings by examining several single nucleotide polymorphisms (SNPs) that were previously genotyped as part of a genome-wide association study in the ADIPOQ gene. Genotyping was also performed for a previously reported risk variant, rs266729, in 1062 individuals with a diagnosis of colorectal cancer and 1062 controls matched on age, gender and ethnicity (Jewish or not Jewish) as part of a population-based case–control study in Israel.

Results:

No evidence was found for an association between ADIPOQ and risk of colorectal cancer. The single nucleotide variant previously associated with decreased risk of colorectal cancer, rs266729, revealed an adjusted odds ratio of 1.04; 95% confidence interval, 0.88–1.23.

Conclusion:

The SNP, rs266729, was not strongly associated with colorectal cancer in patients of Ashkenazi Jewish descent or other ethnic groups in Israel.

Diabetes, gestational diabetes and the risk of cancer in women: epidemiologic evidence and possible biologic mechanisms

At present, more than 10% of adult American women are diagnosed with diabetes mellitus (DM). As the prevalence of the disease increases, there is greater interest in the relationship between DM and other major health issues, such as cancer - one of the leading causes of death in the western world. This paper reviews the literature on the relationship between Type 2 DM and different types of cancer among women. We discuss the possible biological mechanisms that may link diabetes and cancer, important confounders, shared risk factors and a short review of the epidemiologic literature on the association between Type 2 DM and cancer of specific organs (pancreas, liver, colorectal, bladder, endometrial, non-Hodgkin's lymphoma and breast). We also examine the association between gestational diabetes, a closely related risk factor for DM in women, and subsequent risk of cancer. Cancer survival of diabetic women is also briefly discussed. The paper concludes with an agenda for future research targeting the relationship between diabetes and cancer.