The adiponectin gene, ADIPOQ, and genetic susceptibility to colon cancer

Molecular pathology of colorectal cancer: The Saudi situation in perspective

Colorectal cancer (CRC) is one of the most common cancers worldwide, and one of the most common causes of cancer deaths. In recent times, significant advancements have been made in elucidating the molecular alterations of the disease, and the results have been an improved understanding of CRC biology, as well as the discovery of biomarkers of diagnostic, prognostic, and therapeutic significance. In this review, an evaluation is carried out of the molecular pathology research of CRC emanating from Saudi Arabia. The verdict is that the data on the molecular alterations in CRC from Saudi patients is at best modest. This dearth of molecular pathology data is aptly reflected in the paucity of molecular markers recommended for testing by the Saudi National Cancer Centre guidelines for CRC management. Large scale multi-institutional and multiregional translational studies are required to generate molecular data that would inform diagnostic, prognostic, and risk-stratification guidelines for Saudi CRC patients.

Dissecting the Molecular Role of ADIPOQ SNPs in Saudi Women Diagnosed with Gestational Diabetes Mellitus

The traditional definition of gestational diabetes mellitus (GDM) is the leading cause of carbohydrate intolerance in hyperglycemia of varying severity, with onset or initial detection during pregnancy. Previous studies have reported a relationship among obesity, adiponectin (ADIPOQ), and diabetes in Saudi Arabia. ADIPOQ is an adipokine that is produced and secreted by adipose tissue involved in the regulation of carbohydrate and fatty acid metabolism. This study investigated the molecular association between rs1501299, rs17846866, and rs2241766 single-nucleotide polymorphisms (SNPs) in ADIPOQ and GDM in Saudi Arabia. Patients with GDM and control patients were selected, and serum and molecular analyses were performed. Statistical analyses were performed on clinical data, Hardy Weinberg Equilibrium, genotype and allele frequencies, multiple logistic regression, ANOVA, haplotype, linkage disequilibrium, as well as MDR and GMDR analyses. The clinical data showed significant differences in various parameters between the GDM and non-GDM groups (p < 0.05). In GDM women with alleles, genotypes, and different genetic models, the rs1501299 and rs2241766 SNPs showed a strong association (p < 0.05). Multiple logistic regression analysis revealed a negative correlation (p > 0.05). This study concluded that rs1501299 and rs2241766 SNPs were strongly associated with GDM in women in Saudi Arabia.

The interaction between glycemic index, glycemic load, and the genetic variant ADIPOQ T45G (rs2241766) in the risk of colorectal cancer: a case-control study in a Korean population

PURPOSE

The glycemic index (GI), glycemic load (GL), and adiponectin level contribute to glycemic response and insulin sensitivity in the body. Studies have shown that tumor development is related to glycemic disorders; however, the results are contradictory. We aimed to investigate the association of GI and GL with colorectal cancer (CRC) risk in a Korean population and their possible interactions with the genetic variant ADIPOQ T45G.

METHODS AND RESULTS

A case-control study including 2096 participants with 695 CRC cases was conducted. The results showed that diets with high GI or GL were significantly associated with an increased risk of CRC [odds ratio (OR) = 5.44, 95% confidence interval (CI) 3.85-7.68; OR = 4.43, 95% CI 3.18-6.15, respectively; all p-trends < 0.001]. Moreover, even with a low-GI and low-GL diet, G/G genotype carriers may have 2.93-fold and 3.77-fold higher risk of rectal cancer compared to carriers of other genotypes (T/T + T/G), (OR = 2.93, 95% CI 1.01-8.59, p-interaction = 0.011 for GI; OR = 3.77, 95% CI 1.46-9.77, p-interaction = 0.025 for GL).

CONCLUSIONS

Overall, our study suggests positive associations of GI and GL with CRC risk. Moreover, the associations of GI and GL with rectal cancer risk could be modified by ADIPOQ T45G in a Korean population. Further studies with larger sample sizes are needed to confirm our findings.

Correlation between adiponectin rs2241766 and rs266729 polymorphisms and risk of papillary thyroid cancer

About 60-80% of thyroid cancer (TC) cases are papillary thyroid cancer (PTC). Studies have shown that serum adiponectin levels are inversely related to the risk of TC and PTC. Aim of the present study was to evaluate the association between adiponectin rs2241766 and rs266729 polymorphisms and risk of PTC. 122 PTC patients and 128 healthy subjects were enrolled in the study. PCR-RFLP and ARMS-PCR methods were used for genotype analysis. The rs266729 polymorphism did not correlate with risk of PTC. As regard rs2241766 polymorphism, the frequency of the GG genotype did not have a significant difference between the two groups, although, PTC cases showed higher frequency of GT genotype compared to controls (OR=2.87, 95% CI=1.56-5.28, P=0.001). We observed a significant association between adiponectin rs2241766 polymorphism and PTC, however, our result showed no significant relationship between adiponectin rs266729 polymorphism and risk of PTC.

Epidemiology of cancer in Saudi Arabia thru 2010-2019: a systematic review with constrained meta-analysis

Background

Cancer is emerging as a major global health-care system challenge with a growing burden worldwide. Due to the inconsistent cancer registry system in Saudi Arabia, the epidemiology of cancer is still dispersed in the country. Consequently, this review aimed to assemble the epidemiological metrics of cancer in Saudi Arabia in light of the available published data during the period from (2010–2019).

Methods

Published literature from Saudi Arabia relating to cancer incidence, prevalence, risk factors, and other epidemiological metrics were accessed through electronic search in Medline/PubMed, Cochrane, Scopus, Web of Knowledge, Google Scholar, and public database that meet the inclusion criteria. Relevant keywords were used during the electronic search about different types of cancers in Saudi Arabia. No filters were used during the electronic searches. Data were pooled and odds ratios (ORs) and 95% confidence interval (95%CI) were calculated. A random-effects meta-analysis was performed to assess the well-determined risk factors associated with different types of cancers.

Results

The most common cancers in Saudi Arabia are breast, colorectal, prostate, brain, lymphoma, kidney and thyroid outnumbering respectively. Their prevalence rates and OR (95%CI) as follow: breast cancer 53% and 0.93 (0.84–1.00); colon-rectal cancer (CRC) 50.9% and 1.2 (0.81–1.77); prostate cancer 42.6% and 3.2 (0.88–31.11); brain/Central Nervous System cancer 9.6% and 2.3 (0.01–4.2); Hodgkin and non-Hodgkin's lymphoma 9.2% and 3.02 (1.48–6.17); kidney cancer 4.6% and 2.05 (1.61–2.61), and thyroid cancer 12.9% and 6.77 (2.34–19.53).

Conclusion

Within the diverse cancers reported from Saudi Arabia, the epidemiology of some cancers magnitude 3-fold in the latest years. This increase might be attributed to the changing in the Saudi population lifestyle (adopting western model), lack of cancer awareness, lack of screening & early detection programs, social barriers toward cancer investigations. Obesity, genetics, sedentary lifestyle, tobacco use, viral infection, and iodine & Vit-D deficiency represent the apparent cancer risk factors in Saudi Arabia.

Association of Candidate Gene Polymorphism with Metabolic Syndrome among Mongolian Subjects: A Case-Control Study

Metabolic syndrome (MetS) is complex and determined by the interaction between genetic and environmental factors and their influence on obesity, insulin resistance, and related traits associated with diabetes and cardiovascular disease risk. Some dynamic markers, including adiponectin (ADIPOQ), brain-derived neurotrophic factor (BDNF), and lipoprotein lipase (LPL), are implicated in MetS; however, the influence of their genetic variants on MetS susceptibility varies in racial and ethnic groups. We investigated the association of single nucleotide polymorphism (SNP)-SNP interactions among nine SNPs in six genes with MetS's genetic predisposition in Mongolian subjects. A total of 160 patients with MetS for the case group and 144 healthy individuals for the control group were selected to participate in this study. Regression analysis of individual SNPs showed that the ADIPOQ + 45GG (odds ratio (OR) = 2.09, p = 0.011) and P⁺P⁺ of LPL PvuII (OR = 2.10, p = 0.038) carriers had an increased risk of MetS. Conversely, G allele of LPL S447X (OR = 0.45, p = 0.036) and PGC-1α 482Ser (OR = 0.26, p = 0.001) allele were estimated as protective factors, respectively. Moreover, a haplotype containing the G-P⁺-G combination was related to MetS. Significant loci were also related to body mass index (BMI), systolic blood pressure (SBP), serum high-density lipoprotein cholesterol (HDL-C), triglyceride (TG), and fasting blood glucose (FBG), adipokines, and insulin as well as insulin resistance (p < 0.05). Our results confirm that ADIPOQ + 45T > G, LPL PvII, and PGC-1α Gly482Ser loci are associated with MetS in Mongolian subjects.

The Association between Adiponectin Single Nucleotide Polymorphisms and Side Effects of Isotretinoin in Acne Patients

Background

Acne is a common condition of pilosebaceous follicle especially among young. Clinically, the most used medication in the treatment of moderate to severe acne is oral isotretinoin. However, interindividual variability in therapeutic response to isotretinoin and many side effects such as musculoskeletal pain, headache, and alteration in lipid profile can be seen with this treatment.

Aim

In this study, the effect of genetic polymorphisms, rs2241766 and rs1501299, of the adiponectin gene was investigated in relation to the side effects of isotretinoin-treated young adult acne patients (n = 230).

Methods

Several biochemical parameters were measured at baseline and after treatments with isotretinoin. The ADIPOQ gene SNPs, rs2241766 and rs1501299, were genotyped in 230 patients.

Results

Alterations in lipid profile with a significant increase of ALT (P=0.007) were detected after isotretinoin treatment. Moreover, percentage change in HDL following isotretinoin treatment was significantly associated with rs1501299 (P=0.008). On the other hand, no associations between examined SNPs and side effects of isotretinoin and other lipid parameters (total cholesterol, LDL, and triglycerides) or liver function enzymes (ALT and AST) were detected.

Conclusions

Current findings showed that rs1501299 of the ADIPOQ gene might be associated with changes in HDL level in acne patients following treatment with isotretinoin.

Association of single nucleotide polymorphisms of adiponectin and leptin genes with breast cancer

Single nucleotide polymorphisms (SNPs) in adiponectin gene [rs1501299 (+276G/T) and rs266729 (-11377C/G)] and one SNP of leptin gene [rs7799039 (-2548G/A)] are known to influence plasma levels of adiponectin and leptin respectively. Literature is scarce on the association of adiponectin gene polymorphism rs266729 with breast cancer. The present study was taken up to study these polymorphisms and their association with breast cancer. Ninety-three patients diagnosed with malignant breast cancer were included as cases along with 186 age matched healthy controls. Adiponectin +276G/T, -11377C/G and leptin -2548G/A polymorphism were studied using polymerase chain reaction (PCR) based restriction fragment length polymorphism (RFLP). Adipokine levels in blood were measured using enzyme linked immunosorbent assay. Adiponectin +276G/T and leptin -2548G/A showed a significant increased risk for breast cancer even after adjusting for confounding variables like present age, age at menarche, age at first child birth and age at menopause. In the subset analysis, based on menopausal state, stronger association was observed between SNP in adiponectin gene +276G/T with the breast cancer in post-menopausal women after adjusting for all other variables. No association was found with adiponectin -11377C/G. No association of the gene polymorphisms with adipokine levels was observed. Also, no significant association was seen for the effect of gene-environment interaction i.e. presence of polymorphism with obesity and menopausal state for any of the SNPs studied. Adiponectin +276G/T is strongly associated with breast cancer in postmenopausal women while leptin -2548G/A polymorphisms is significantly associated with breast cancer irrespective of the menopausal state in south Indian subjects.

Leptin gene variants and colorectal cancer risk: Sex-specific associations

BACKGROUND

High levels of serum leptin and low levels of serum adiponectin are strongly correlated with obesity, a well-established risk factor for colorectal cancer (CRC). Growing evidence suggests that dysregulation of leptin and adiponectin levels may play an etiological role in colorectal carcinogenesis. We evaluated 20 candidate variants in 4 genes previously shown to alter serum leptin and adiponectin levels for associations with obesity (BMI>30 kg/m2) and CRC risk.

METHODS

We analyzed 6,246 CRC cases and 7,714 population-based controls from 11 studies within the Genetics and Epidemiology of Colorectal Cancer Consortium (GECCO). Associations of each variant with obesity or CRC were evaluated using multivariate logistic regression models stratified by sex and adjusted for age, a study variable, and the first three principal components of genetic ancestry. Gene-specific False Discovery Rate (FDR)-adjusted p-values <0.05 denoted statistical significance.

RESULTS

Two variants in the leptin gene showed statistically significant associations with CRC among women: LEP rs2167270 (OR = 1.13, 95% CI: 1.06-1.21) and LEP rs4731426 (OR = 1.09, 95% CI: 1.02-1.17). These associations remained significant after adjustment for obesity, suggesting that leptin SNPs may influence CRC risk independent of obesity. We observed statistically significant interactions of the leptin variants with hormone replacement therapy (HRT) for CRC risk; these variant associations were strengthened when analyses were restricted to post-menopausal women with low estrogen exposure, as estimated by 'never use' of HRT and/or non-obese BMI. No variants were associated with CRC among men.

CONCLUSIONS

Leptin gene variants may exhibit sex-specific associations with CRC risk. Endogenous and exogenous estrogen exposure may modify the association between these variants, leptin levels, and CRC risk.

Low circulating total adiponectin, especially its non-high-molecular weight fraction, represents a promising risk factor for colorectal cancer: a meta-analysis

Aim

The principal goal of this meta-analysis is to test the hypothesis that circulating total adiponectin or certain fractions may represent a promising biological candidate in modulating the risk of colorectal cancer.

Methods

The processes of paper identification, paper selection and data extraction were accomplished independently by two authors. Effect-size estimates were expressed as weighted mean difference (WMD) and 95% confidence interval (95% CI). A total of 31 papers including 48 qualified studies (7,554 patients with colorectal cancer and 9,798 controls) were meta-analyzed.

Results

Pooling all studies found that circulating total adiponectin was significantly lower in patients with colorectal cancer than in controls (WMD: −0.76 µg/mL, 95% CI: −1.20 to −0.32, p=0.001), with significant heterogeneity (I²: 94.2%) and low publication bias (Egger’s p=0.336). By adiponectin fractions, the difference in high-molecular weight (HMW) adiponectin was comparable between the two groups (WMD: −0.22 µg/mL, 95% CI: −0.70 to 0.25, p=0.350), while non-HMW adiponectin was significantly lower in patients with colorectal cancer than in controls (WMD: −0.27 µg/mL, 95% CI: −0.35 to −0.19, p<0.001), with marginal heterogeneity (I²: 52.3%). Subgroup analysis revealed that effect-size estimates were heterogeneous when grouping studies by cancer subtype, region, study design, matching status, gender and obesity. Further meta-regression analysis indicated that age and gender were significant potential sources of heterogeneity. The results showed the studied subgroups were not subject to publication bias (Egger’s p<0.1).

Conclusion

Our data collectively indicate that low circulating total adiponectin, especially its non-HMW fraction, represents a promising risk factor for colorectal cancer. Further studies are needed to explore underlying mechanisms.

FABP4 blocker attenuates colonic hypomotility and modulates white adipose tissue-derived hormone levels in mouse models mimicking constipation-predominant IBS

BACKGROUND

The role of fatty acid binding protein 4 (FABP4) in lower gastrointestinal (GI) motility is unknown. We aimed to verify the effect of inhibition of FABP4 on GI transit in vivo, and to determine the expression of FABP4 in mouse and human tissues.

METHODS

Fatty acid binding protein 4 inhibitor, BMS309403, was administered acutely or chronically for 6 and 13 consecutive days and its effect on GI transit was assessed in physiological conditions and in loperamide-induced constipation. Intracellular recordings were made to examine the effects of BMS309403 on colonic excitatory and inhibitory junction potentials. Abdominal pain was evaluated using behavioral pain response. Localization and expression of selected adipokines were determined in the mouse colon and serum using immunohistochemistry and Enzyme-Linked ImmunoSorbent Assay respectively. mRNA expression of FABP4 and selected adipokines in colonic and serum samples from irritable bowel syndrome (IBS) patients and control group were assessed.

KEY RESULTS

Acute injection of BMS309403 significantly increased GI motility and reversed inhibitory effect of loperamide. BMS309403 did not change colonic membrane potentials. Chronic treatment with BMS309403 increased the number of pain-induced behaviors. In the mouse serum, level of resistin was significantly decreased after acute administration; no changes in adiponectin level were detected. In the human serum, level of adiponectin and resistin, but not of FABP4, were significantly elevated in patients with constipation-IBS (IBS-C). FABP4 mRNA expression was significantly downregulated in the human colon in IBS-C.

CONCLUSIONS AND INFERENCES

Fatty acid binding protein 4 may be involved in IBS pathogenesis and become a novel target in the treatment of constipation-related diseases.

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.

Common polymorphisms of the hOGG1, APE1 and XRCC1 genes correlate with the susceptibility and clinicopathological features of primary angle-closure glaucoma

The present case study aims to elucidate the correlation between the human 8-hydroxyguanineglycosylase (hOGG1), APE1 and X-ray repair cross-complementing gene 1 (XRCC1) gene polymorphisms to the susceptibility and clinicopathological features of primary angle closure glaucoma (PACG) in a Chinese Han population. Blood samples were obtained from 258 PACG patients (case group) and 272 healthy volunteers (control group). PCR with sequence-specific primer (PCR-SSP) was used to determine the allele frequencies and genotype distributions of the hOGG1, APE1 and XRCC1 genes. The risk factors of PACG were determined using logistic regression analysis. The results indicated that hOGG1 Ser326Cys, APE1 Asp148Glu and XRCC1 Arg399Gln polymorphisms were correlated with the risk of PACG. Furthermore, there were thicker corneas, higher intraocular pressure (IOP) and a shorter axial length in patients carrying the mutant genotypes of hOGG1 Ser326Cys (Ser/Cys + Cys/Cys), APE1 Asp148Glu (Asp/Glu + Glu/Glu) and XRCC1 Arg399Gln (Arg/Gln + Glu/Glu) than those carrying the corresponding wild-type genotypes. According to the logistic regression analysis, Asp148Glu and Arg399Gln polymorphisms, a short axial length and high IOP are major risk factors for PACG. These findings reveal that hOGG1 Ser326Cys, APE1 Asp148Glu and XRCC1 Arg399Gln polymorphisms are correlated with the risk and clinicopathological features of PACG in a Chinese Han population.

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.

Association of adiponectin receptor 1 gene - 106 C > T variant with susceptibility to colorectal cancer

Background

Colorectal cancer (CRC) is the fourth leading cause of cancer-related death around the world and accumulated evidence indicates the association between CRC and obesity and insulin resistance.

Objectives

Regarding the role of adiponectin in obesity and insulin resistance, we explored whether genetic variants in adiponectin (ADIPOQ) and adiponectin receptor 1 (ADIPOR1) are associated with CRC risk.

Materials and methods

ADIPOQ (rs2241766) and ADIPOR1 (rs2275738) gene variants were genotyped in 261 cases with CRC and 339 controls using PCR-RFLP method.

Results

In this study, no significant difference was observed for ADIPOQ gene rs2241766 variant between the cases and controls. However, carriers of the ADIPOR1 (rs2275738) “CC + CT” genotype compared with “TT” genotype occurred more frequently in the cases with CRC than the controls, and the difference remained significant after adjustment for age, BMI, sex, smoking status, NSAID use, and family history of CRC (P = 0.048; OR = 1.49, 95%CI = 1.01–2.20). Interestingly, after adjustment for confounding factors the ADIPOR1 “CC + TC” genotype compared with “TT” genotype was also associated with an increased risk for obesity in the cases (P = 0.040; OR = 1.86, 95%CI = 1.03–3.36).

Conclusions

Our findings suggest for the first time that the − 106 C > T (rs2275738) variant of ADIPOR1 gene may be a genetic contributor to CRC and obesity risk in the cases with CRC. However, further studies with bigger sample size are needed to validate these findings.

Adiponectin and colorectal cancer

Colorectal cancer is an obesity-related malignancy. Adiponectin is an adipokine produced exclusively by adipose tissue, and its concentration in the serum is reduced in obesity. A low serum level of adiponectin is associated with an increased risk of various types of malignancies including colorectal cancer. These facts suggest that the epidemiological link between obesity and cancer may have a significant association with adiponectin. Although numerous studies of colorectal cancer have been reported, the results are conflicting about the anti-cancer effect of adiponectin, and how adiponectin affects carcinogenesis or cancer development remains controversial. Because adiponectin has multiple systemic effects and exists as a high serum concentration protein, the main role of adiponectin should be regulation of homeostasis, and it would not likely act as an anti-cancerous hormone. However, as epidemiological evidence shows, a low adiponectin level may be a basic risk factor for colorectal cancer. We speculate that when the colonic epithelium is stimulated or damaged by another carcinogen under the condition of a low adiponectin level, carcinogenesis is promoted and cancer development is facilitated. In this report, we summarize recent findings of the correlation between adiponectin and colorectal cancer and investigate the effect of adiponectin on colorectal cancer.

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.

Adiponectin Gene Polymorphisms are Associated with Increased Risk of Colorectal Cancer

Background

This meta-analysis investigates the associations of adiponectin (ADIPOQ) genetic polymorphisms with the susceptibility to colorectal cancer (CRC).

Material/Methods

2 reviewers independently searched 6 databases – PubMed, Cochrane Library, Ovid, Embase, China National Knowledge Infrastructure (CNKI) and Wanfang databases – to identify published studies relevant to adiponectin gene polymorphisms and CRC. Studies retrieved from database searches were screened using our stringent inclusion and exclusion criteria. Full texts of the selected studies were accessed and related data was extracted using a standardized data extraction form. Comprehensive Meta-analysis 2.0 software was used for statistical analyses.

Results

A total of 188 studies were initially retrieved from database search, and 6 studies were eventually selected, through a rigorous screening process, for inclusion in this meta-analysis. The 6 studies contained a total of 1897 patients (Asians: 1190; white: 707) with CRC in case group and 2475 healthy controls (Asians: 1325; white: 1150) in the control group. Results of the current meta-analysis revealed that the rs2241766 T>G single-nucleotide polymorphisms (SNP) increase the risk of CRC; rs1501299 G>T under dominant model was associated with increased risk of CRC; and rs266729 C>G SNP under allele model conferred an increased risk of CRC.

Conclusions

Our meta-analysis strongly suggests that the ADIPOQ rs2241766 T>G, rs1501299 G>T, and rs266729 C>G SNPs correlate with an increased risk of CRC.

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.

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.

Differential gene expression of the key signalling pathway in para-carcinoma, carcinoma and relapse human pancreatic cancer

Pancreatic cancer (PC) has a high rate of mortality and a poorly understood mechanism of progression. Investigation of the molecular mechanism of PC and exploration of the specific markers for early diagnosis and specific targets of therapy are key points to prevent and treat PC effectively and to improve their prognosis. In our study, expression profiles experiment of para-carcinoma, carcinoma and relapse human PC was performed using Agilent human whole genomic oligonucleotide microarrays with 45 000 probes. Differentially expressed genes related with PC were screened and analysed further by Gene Ontology term analysis and Kyoto encyclopaedia of genes and genomes pathway analysis. Our results showed that there were 3853 differentially expressed genes associated with pancreatic carcinogenesis and relapse. In addition, our study found that PC was related to the Jak-STAT signalling pathway, PPAR signalling pathway and Calcium signalling pathway, indicating their potential roles in pancreatic carcinogenesis and progress.

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.

Gene Polymorphisms of ADIPOQ +45T>G, UCP2 -866G>A, and FABP2 Ala54Thr on the Risk of Colorectal Cancer: A Matched Case-Control Study

As insulin resistance (IR) is an established risk factor for colorectal cancer (CRC), we explored the association between each of the IR-related gene polymorphisms of adiponectin (ADIPOQ) rs2241766, uncoupling protein 2 (UCP2) rs659366, and fatty acid-binding protein (FABP2) rs1799883 and CRC risk. Genotyping of blood samples and collection of lifestyle and dietary habits were performed for 400 case-control pairs. Unconditional logistic regression (ULR) was applied to assess the effects of the three single nucleotide polymorphisms (SNP), environmental factors. Both ULR and generalized multifactor dimensionality reduction (GMDR) were used to test the gene-gene and gene-environment interactions on CRC risk. Subjects carrying the ADIPOQ rs2241766 TG+GG genotype had a higher CRC risk than those carrying the TT genotype (OR = 1.429, 95% CI 1.069–1.909). The additive and multiplicative interactions between ADIPOQ rs2241766 and FABP2 rs1799883 on CRC were found by ULR (RERI = 0.764, 95%CI 0.218∼1.311, AP = 0.514, 95%CI 0.165∼0.864, S = −1.745, 95%CI is unachievable, and P_multi = 0.017, respectively). Furthermore, the high order gene-gene interaction of the three SNPs were found by GMDR (P = 0.0107). A significant dosage effect with an increasing number of risk genotypes was observed as the risk of CRC increased (P_trend = 0.037). In GMDR, the gene-environment interaction among the three SNPs and red meat consumption on CRC risk was significant (P = 0.0107). Compared with subjects with low red meat consumption and null risk genotypes, those with high-red meat consumption and three risk genotypes had 3.439-fold CRC risk (95% CI 1.410–8.385). In conclusion, the results showed that the ADIPOQ rs2241766 TG+GG genotype increased CRC risk. Given the complexity of the carcinogen for CRC, ADIPOQ rs2241766, UCP2 rs659366, FABP2 rs1799883 and red meat consumption potentially worked together in affecting CRC risk.

Three adiponectin rs1501299G/T, rs822395A/C, and rs822396A/G polymorphisms and risk of cancer development: a meta-analysis

Many epidemiological studies have studied the associations between adiponectin rs1501299G/T, rs822395A/C, and rs822396A/G polymorphisms and risk of cancer development, while conflicting results have been reported. Therefore, we conducted a meta-analysis to assess the associations. We retrieved the following databases: Medline, Embase, Web of Science, and Wanfang, and the latest update date was 15th of August 2012. Odds ratio (OR) and corresponding 95 % confidence interval (95 % CI) were calculated by using fixed- or random-effect model. Overall, there were 13 case-control studies consisting of 7,902 subjects for adiponectin rs1501299G/T, seven studies consisting of 6,209 subjects for rs822395A/C, and seven studies consisting of 5,791 subjects for rs822396A/G polymorphism in this study. Combined analyses indicated that neither adiponectin rs822395A/C nor rs822396A/G was associated with risk of cancer incidence (OR (95 % CI) 0.91 (0.77-1.77), P z test = 0.26 for CC vs. AA and 0.96 (0.87-1.05) for C carriers vs. A carriers, P z test = 0.33 for rs822395A/C; 0.88 (0.53-1.47) for GG vs. AA, P z test = 0.63 and 0.94 (0.84-1.04) for G carriers vs. A carriers, P z test = 0.24 for rs822396A/G polymorphism). Similarly, combined analysis also indicated that adiponectin rs1501299G/T polymorphism was not associated with risk of cancer development (OR (95 % CI) 0.86 (0.73-1.01) for TT vs. GG, P z test = 0.07 and 1.17 (0.98-1.39), P z test = 0.08). However, when stratified analyses were conducted, the result indicated that T allele was significantly associated with increased cancer risk for Caucasians (OR (95 % CI) 1.28 (1.06-1.64) and P z test = 0.01 for G carriers vs. T carriers) and associated with increased risk of colorectal cancer development while with decreased risk of prostate cancer incidence compared to G allele (OR (95 % CI) 1.34 (1.14-1.57), P z test < 0.01 for G carriers vs. T carriers for colorectal cancer; 0.80 (0.65-0.97), P z test = 0.03 for TG vs. GG for prostate cancer). In summary, this meta-analysis indicated that adiponectin rs1501299G/T, rather than rs822395A/C and rs822396A/G polymorphism, was associated with risk of cancer development, especially for colorectal and prostate 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.