Association between insulin receptor substrate 1 Gly972Arg polymorphism and cancer risk

The strategic involvement of IRS in cancer progression

Insulin Receptor Substrate (IRS), an intracellular molecule devoid of an intrinsic kinase activity, is activated upon binding to IR which thereby works as a scaffold, organizing all signaling complexes and initiating the signaling process downstream. The level of IRS proteins and their stability in the cell is mostly maintained through the phosphorylation status of their tyrosine and serine residues. IRS is positively regulated by phosphorylation of its Tyr residues whereas a Ser residue phosphorylation attenuates it, although there exist some exceptions as well. Other post-translational modifications like O-linked glycosylation, N-linked glycosylation and acetylation also play a prominent role in IRS regulation. Since the discovery of the Warburg effect, people have been curious to find out all possible signaling networks and molecules that could lead to cancer and no doubt, the insulin signaling pathway is identified as one such pathway, which is highly deregulated in cancers. Eminent studies reveal that IRS is a pertinent regulator of cancer and is highly overexpressed in the five most commonly occurring cancers namely- Prostate, Ovarian, Breast, Colon and Lung cancers. IRS1 and IRS2 family members are actively involved in the progression, invasion and metastasis of these cancers. Recently, less studied IRS4 has also emerged as a contributor in ovarian, breast, colorectal and lung cancer, but no such studies related to IRS4 are found in Prostate cancer. The involvement of other IRS family members in cancer is still undiscovered and so paves the way for further exploration. This review is a time-lapse study of IRSs in the context of cancer done over the past two decades and it highlights all the major discoveries made till date, in these cancers from the perspective of IRS.

Genetic architecture of mammographic density as a risk factor for breast cancer: a systematic review

BACKGROUND

Mammography Density (MD) is a potential risk marker that is influenced by genetic polymorphisms and can subsequently modulate the risk of breast cancer. This qualitative systematic review summarizes the genes and biological pathways involved in breast density and discusses the potential clinical implications in view of the genetic risk profile for breast density.

METHODS

The terms related to "Common genetic variations" and "Breast density" were searched in Scopus, PubMed, and Web of Science databases. Gene pathways analysis and assessment of protein interactions were also performed.

RESULTS

Eighty-six studies including 111 genes, reported a significant association between mammographic density in different populations. ESR1, IGF1, IGFBP3, and ZNF365 were the most prevalent genes. Moreover, estrogen metabolism, signal transduction, and prolactin signaling pathways were significantly related to the associated genes. Mammography density was an associated phenotype, and eight out of 111 genes, including COMT, CYP19A1, CYP1B1, ESR1, IGF1, IGFBP1, IGFBP3, and LSP1, were modifiers of this trait.

CONCLUSION

Genes involved in developmental processes and the evolution of secondary sexual traits play an important role in determining mammographic density. Due to the effect of breast tissue density on the risk of breast cancer, these genes may also be associated with breast cancer risk.

Multi-Omics Data Analysis Uncovers Molecular Networks and Gene Regulators for Metabolic Biomarkers

The insulin-like growth factors (IGFs)/insulin resistance (IR) axis is the major metabolic hormonal pathway mediating the biologic mechanism of several complex human diseases, including type 2 diabetes (T2DM) and cancers. The genomewide association study (GWAS)-based approach has neither fully characterized the phenotype variation nor provided a comprehensive understanding of the regulatory biologic mechanisms. We applied systematic genomics to integrate our previous GWAS data for IGF-I and IR with multi-omics datasets, e.g., whole-blood expression quantitative loci, molecular pathways, and gene network, to capture the full range of genetic functionalities associated with IGF-I/IR and key drivers (KDs) in gene-regulatory networks. We identified both shared (e.g., T2DM, lipid metabolism, and estimated glomerular filtration signaling) and IR-specific (e.g., mechanistic target of rapamycin, phosphoinositide 3-kinases, and erb-b2 receptor tyrosine kinase 4 signaling) molecular biologic processes of IGF-I/IR axis regulation. Next, by using tissue-specific gene–gene interaction networks, we identified both well-established (e.g., IRS1 and IGF1R) and novel (e.g., AKT1, HRAS, and JAK1) KDs in the IGF-I/IR-associated subnetworks. Our results, if validated in additional genomic studies, may provide robust, comprehensive insights into the mechanisms of IGF-I/IR regulation and highlight potential novel genetic targets as preventive and therapeutic strategies for the associated diseases, e.g., T2DM and cancers.

Mendelian Randomization Study: The Association Between Metabolic Pathways and Colorectal Cancer Risk

Background: The roles of obesity-related biomarkers and their molecular pathways in the development of postmenopausal colorectal cancer (CRC) have been inconclusive. We examined insulin resistance (IR) as a major hormonal pathway mediating the association between obesity and CRC risk in a Mendelian randomization (MR) framework.

Methods: We performed MR analysis using individual-level data of 11,078 non-Hispanic white postmenopausal women from our earlier genome-wide association study. We identified four independent single-nucleotide polymorphisms associated with fasting glucose (FG), three with fasting insulin (FI), and six with homeostatic model assessment–IR (HOMA-IR), which were not associated with obesity. We estimated hazard ratios (HRs) for CRC by adjusting for potential confounding factors plus genetic principal components.

Results: Overall, we observed no direct association between combined 13 IR genetic instruments and CRC risk (HR = 0.96, 95% confidence interval [CI]: 0.78–1.17). In phenotypic analysis, genetically raised HOMA-IR exhibited its effects on the increased risk and FG and FI on the reduced risk for CRC, but with a lack of statistical power. Subgroup analyses by physical activity level and dietary fat intake with combined phenotypes showed that genetically determined IR was associated with reduced CRC risk in both physical activity-stratified (single contributor: MTRR rs722025; HR = 0.12, 95% CI: 0.02–0.62) and high-fat diet subgroups (main contributor: G6PC2 rs560887; HR = 0.59, 95% CI: 0.37–0.94).

Conclusions: Complex evidence was observed for a potential causal association between IR and CRC risk. Our findings may provide an additional value of intervention trials to lower IR and reduce CRC risk.

Association of IRS1 Gly972Arg and IRS2 Gly1057Asp polymorphisms with gastric cancer in Turkish subjects

Insulin receptor substrate (IRS) proteins are cytoplasmic adaptors that transmit the signal from the IR and insulin-like growth factor-1 receptor to effector proteins. Overexpression of IRS proteins has been indicated to be linked to cancer development. In addition to their expression profiles, studies have indicated that polymorphisms of IRS1 and IRS2 are also associated with the susceptibility to numerous cancer types. IRS1 Gly972Arg and IRS2 Gly1057Asp are the common variants of these genes. The present study aimed to determine the association of IRS1 Gly972Arg and IRS2 Gly1057Asp polymorphisms with gastric cancer development. The study included 100 patients with gastric cancer and 100 controls. Single-nucleotide polymorphisms were detected by real-time PCR using Taqman assays. The results suggested that in individuals with the IRS1 Gly/Arg genotype, the odds of having gastric cancer was increased by 7.891-fold (95% CI: 3.251-19.154, P<0.001) and in individuals with the IRS1 Arg/Arg genotype, it was increased by 22.716-fold (95% CI: 6.311-81.761, P<0.001) compared with those with the IRS1 Gly/Gly genotype. Although the IRS2 Gly1057Asp genotype analysis suggested that subjects with the Asp/Asp genotype had a 2,311-fold increased odds of having gastric cancer compared to those with the Gly/Gly genotype, the result was not statistically significant (95% CI: 0.800-6.678, P=0.122). The combined effects of the IRS1 and IRS2 variants on gastric cancer were also determined. The results suggested that individuals with Gly/Arg+Gly/Asp and Gly/Arg+Asp/Asp genotypes had a higher odds of having gastric cancer compared to individuals of the Gly/Gly+Gly/Gly genotype (P=0.001 and P=0.027, respectively). In conclusion, the present results suggested that the IRS1 Gly972Arg and IRS2 Gly1057Asp variations may be associated with an increased susceptibility to develop gastric cancer. Further studies with larger sample sizes are required to support the present results and to explore the use of these variations as a biomarker for gastric cancer.

The effects of genetic variants related to insulin metabolism pathways and the interactions with lifestyles on colorectal cancer risk

OBJECTIVES

Genetic variants in metabolic signaling pathways may interact with lifestyle factors, such as dietary fatty acids, influencing postmenopausal colorectal cancer (CRC) risk, but these interrelated pathways are not fully understood.

METHODS

In this study, we examined 54 single-nucleotide polymorphisms (SNPs) in genes related to insulin-like growth factor-I/insulin traits and their signaling pathways and lifestyle factors in relation to postmenopausal CRC, using data from 6,539 postmenopausal women in the Women's Health Initiative Harmonized and Imputed Genome-Wide Association Studies. By employing a two-stage random survival forest analysis, we evaluated the SNPs and lifestyle factors by ranking them according to their predictive value and accuracy for CRC.

RESULTS

We identified four SNPs (IRS1 rs1801123, IRS1 rs1801278, AKT2 rs3730256, and AKT2 rs7247515) and two lifestyle factors (age and percentage calories from saturated fatty acids) as the top six most influential predictors for CRC risk. We further examined interactive effects of those factors on cancer risk. In the individual SNP analysis, no significant association was observed, but the combination of the four SNPs, age, and percentage calories from saturated fatty acid (≥11% per day) significantly increased the risk of CRC in a gene and lifestyle dose-dependent manner.

CONCLUSIONS

Our findings provide insight into gene-lifestyle interactions and will enable researchers to focus on individuals with risk genotypes to promote intervention strategies. Our study suggests the careful use of data on potential genetic targets in clinical trials for cancer prevention to reduce the risk for CRC in postmenopausal women.

Post genome-wide gene-environment interaction study: The effect of genetically driven insulin resistance on breast cancer risk using Mendelian randomization

PURPOSE

The role of insulin resistance (IR) in developing postmenopausal breast cancer has not been thoroughly resolved and may be confounded by lifestyle factors such as obesity. We examined whether genetically determined IR is causally associated with breast cancer risk.

METHODS

We conducted Mendelian randomization (MR) analyses using individual-level data from our previous meta-analysis of a genome-wide association study (GWAS) (n = 11,109 non-Hispanic white postmenopausal women). Four single-nucleotide polymorphisms were associated with fasting glucose (FG), 2 with fasting insulin (FI), and 6 with homeostatic model assessment-IR (HOMA-IR) but were not associated with obesity. We used this GWAS to employ hazard ratios (HRs) for breast cancer risk by adjusting for potential confounding factors.

RESULTS

No direct association was observed between comprising 12 IR genetic instruments and breast cancer risk (HR = 0.93, 95% CI: 0.76-1.14). In phenotype-specific analysis, genetically elevated FG was associated with reduced risk for breast cancer (main contributor of this MR-effect estimate: G6PC2 rs13431652; HR = 0.59, 95% CI: 0.35-0.99). Genetically driven FI and HOMA-IR were not significantly associated. Stratification analyses by body mass index, exercise, and dietary fat intake with combined phenotypes showed that genetically elevated IR was associated with greater breast cancer risk in overall obesity and inactive subgroups (single contributor: MTRR/LOC729506 rs13188458; HR = 2.21, 95% CI: 1.03-4.75).

CONCLUSIONS

We found complex evidence for causal association between IR and risk of breast cancer, which may support the potential value of intervention trials to lower IR and reduce breast cancer risk.

The Role of Polymorphisms in Genes of PI3K/Akt Signaling Pathway on Prostate

Background and Objective: Increasing evidence suggested that polymorphisms in genes of PI3K/Akt pathway were closely related to prostate cancer (PCa) risk. Nevertheless, these results are controversial and inconclusive. Here, we conducted a comprehensive updated meta-analysis and systematic review to precisely illustrate the association between polymorphisms in genes of PI3K/Akt signaling pathway and PCa risk.

Materials and Methods: The gene set of PI3K/Akt pathway was referenced from the Kyoto Encyclopedia of Genes and Genomes (KEGG) website. Relevant studies were identified by the systematically researching on PubMed, Web of Science and Google Scholar databases up to October 1, 2017. The odds ratios (ORs) with a corresponding 95% confidential intervals (95%CIs) were applied to test their associations. All the analyses were conducted by using Stata 12.0 (Stata Corporation, USA).

Results: Finally, 38 articles comprising 62 case-control studies were enrolled for 13 polymorphisms in genes of PI3K/Akt pathway. However, overall results failed to present a positive association between polymorphisms in genes of PI3K/Akt pathway and PCa risk. Nevertheless, in the subgroup analysis by ethnicity, we identified that IL-6-rs1800795 polymorphism was associated with an increased risk of PCa for Caucasian individuals in dominant model (MM + MW vs. WW: OR = 1.245, 95%CI = 1.176-1.318, P < 0.001).

Conclusion: Our work suggests that polymorphisms in genes of PI3K/Akt Signaling Pathway are not risk factor for PCa. Further well-designed studies with larger samples and precise designs are demanded to corroborate our findings.

Genetic Variants in Metabolic Signaling Pathways and Their Interaction with Lifestyle Factors on Breast Cancer Risk: A Random Survival Forest Analysis

Genetic variants in the insulin-like growth factor-I (IGF-I)/insulin resistance axis may interact with lifestyle factors, influencing postmenopausal breast cancer risk, but these interrelated pathways are not fully understood. In this study, we examined 54 single-nucleotide polymorphisms (SNP) in genes related to IGF-I/insulin phenotypes and signaling pathways and lifestyle factors in relation to postmenopausal breast cancer, using data from 6,567 postmenopausal women in the Women's Health Initiative Harmonized and Imputed Genome-Wide Association Studies. We used a machine-learning method, two-stage random survival forest analysis. We identified three genetic variants (AKT1 rs2494740, AKT1 rs2494744, and AKT1 rs2498789) and two lifestyle factors [body mass index (BMI) and dietary alcohol intake] as the top five most influential predictors for breast cancer risk. The combination of the three SNPs, BMI, and alcohol consumption (≥1 g/day) significantly increased the risk of breast cancer in a gene and lifestyle dose-dependent manner. Our findings provide insight into gene-lifestyle interactions and will enable researchers to focus on individuals with risk genotypes to promote intervention strategies. These data also suggest potential genetic targets in future intervention/clinical trials for cancer prevention in order to reduce the risk for breast cancer in postmenopausal women. Cancer Prev Res; 11(1); 44-51. ©2017 AACR.

Genetic variants and traits related to insulin-like growth factor-I and insulin resistance and their interaction with lifestyles on postmenopausal colorectal cancer risk

Genetic variants and traits in metabolic signaling pathways may interact with lifestyle factors such as obesity, physical activity, and exogenous estrogen (E), influencing postmenopausal colorectal cancer (CRC) risk, but these interrelated pathways are not fully understood. In this case-cohort study, we examined 33 single-nucleotide polymorphisms (SNPs) in genes related to insulin-like growth factor-I (IGF-I)/ insulin resistance (IR) traits and signaling pathways, using data from 704 postmenopausal women in Women’s Health Initiative Observation ancillary studies. Stratifying by the lifestyle modifiers, we assessed the effects of IGF-I/IR traits (fasting total and free IGF-I, IGF binding protein-3, insulin, glucose, and homeostatic model assessment–insulin resistance) on CRC risk as a mediator or influencing factor. Six SNPs in the INS, IGF-I, and IGFBP3 genes were associated with CRC risk, and those associations differed between non-obese/active and obese/inactive women and between E nonusers and users. Roughly 30% of the cancer risk due to the SNP was mediated by IGF-I/IR traits. Likewise, carriers of 11 SNPs in the IRS1 and AKT1/2 genes (signaling pathway–related genetic variants) had different associations with CRC risk between strata, and the proportion of the SNP–cancer association explained by traits varied from 30% to 50%. Our findings suggest that IGF-I/IR genetic variants interact with obesity, physical activity, and exogenous E, altering postmenopausal CRC risk, through IGF-I/IR traits, but also through different pathways. Unraveling gene–phenotype–lifestyle interactions will provide data on potential genetic targets in clinical trials for cancer prevention and intervention strategies to reduce CRC risk.

Interaction of insulin-like growth factor-I and insulin resistance-related genetic variants with lifestyle factors on postmenopausal breast cancer risk

PURPOSE

Genetic variants and traits in metabolic signaling pathways may interact with obesity, physical activity, and exogenous estrogen (E), influencing postmenopausal breast cancer risk, but these inter-related pathways are incompletely understood.

METHODS

We used 75 single-nucleotide polymorphisms (SNPs) in genes related to insulin-like growth factor-I (IGF-I)/insulin resistance (IR) traits and signaling pathways, and data from 1003 postmenopausal women in Women's Health Initiative Observation ancillary studies. Stratifying via obesity and lifestyle modifiers, we assessed the role of IGF-I/IR traits (fasting IGF-I, IGF-binding protein 3, insulin, glucose, and homeostatic model assessment-insulin resistance) in breast cancer risk as a mediator or influencing factor.

RESULTS

Seven SNPs in IGF-I and INS genes were associated with breast cancer risk. These associations differed between non-obese/active and obese/inactive women and between exogenous E non-users and users. The mediation effects of IGF-I/IR traits on the relationship between these SNPs and cancer differed between strata, but only roughly 35% of the cancer risk due to the SNPs was mediated by traits. Similarly, carriers of 20 SNPs in PIK3R1, AKT1/2, and MAPK1 genes (signaling pathways-genetic variants) had different associations with breast cancer between strata, and the proportion of the SNP-cancer relationship explained by traits varied 45-50% between the strata.

CONCLUSIONS

Our findings suggest that IGF-I/IR genetic variants interact with obesity and lifestyle factors, altering cancer risk partially through pathways other than IGF-I/IR traits. Unraveling gene-phenotype-lifestyle interactions will provide data on potential genetic targets in clinical trials for cancer prevention and intervention strategies to reduce breast cancer risk.

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 Single Nucleotide Polymorphisms in Gamma-Aminobutyric Acid B Receptor, Insulin Receptor Substrate-1, and Hypocretin Neuropeptide Precursor Genes and Susceptibility to Obstructive Sleep Apnea Hypopnea Syndrome in a Chinese Han Population

OBJECTIVE

To investigate genotype-phenotype changes between rs29230 in γ-aminobutyric acid B receptor (GABBR1), rs1801278 in insulin receptor substrate-1 (IRS-1), and rs9902709 in hypocretin neuropeptide precursor (HCRT) and obstructive sleep apnea hypopnea syndrome (OSAHS) in Chinese Han individuals.

MATERIALS AND METHODS

A total of 130 patients with OSAHS and 136 age- and gender-matched healthy controls were enrolled in this study. A brief description of DNA extraction and genotyping is given. Multivariate unconditional logistic regression analysis adjusted for gender and age was used to estimate the associations of single nucleotide polymorphisms (SNPs) rs29230 (GABBR1), rs1801278 (IRS-1), and rs9902709 (HCRT) with OSAHS risk. Subgroup analysis was performed to evaluate differences in these SNPs among subgroups according to gender, body mass index (BMI), and severity of disease.

RESULTS

Genotype and allele frequencies of rs29230 were significantly different between cases and controls (p = 0.0205 and p = 0.0191, respectively; odds ratio = 0.493, 95% confidence interval = 0.271-0.896), especially for male patients (p = 0.0259 and p = 0.0202, respectively). Subgroup analysis according to BMI also revealed a significant allele difference for rs29230 between cases and controls in the overweight subgroup (p = 0.0333). Furthermore, allele and genotype frequencies of rs1801278 showed significant differences between cases and controls (p = 0.0488 and p = 0.0471, respectively). However, no association was observed between rs9902709 and OSAHS risk (p = 0.2762), and no differences were identified in other subgroups.

CONCLUSION

In this study, there was an association between variants of rs29230 and rs1801278 and OSAHS risk in the Chinese Han population but not for rs9902709.

Association between NQO1 C609T polymorphism and prostate cancer risk

Published studies on the association between NQO1 C609T polymorphism and prostate cancer risk have yielded conflicting results. Thus, a systemic review and meta-analysis of published studies were performed to assess the possible association. All eligible studies of NQO1 C609T polymorphism and prostate cancer risk were collected from the PubMed and the Cochrane Library. Statistical analyses were performed by Review Manage 5.0 and Stata 11.0. A total of 6 available studies were considered in the present meta-analysis, with 717 cases and 1,794 controls. When all groups were pooled, there was no evidence that NQO1 C609T had significant association with prostate cancer under additive, recessive, dominant, and allelic models. When stratifying for the race, our analysis suggested that NQO1 C609T was associated with prostate cancer risk in Asians when using dominant (TT + CT vs CC: OR = 1.419, 95 % CI = 1.053 - 1.913, P = 0.021) and allelic models (OR = 1.337, 95 % CI = 1.014 - 1.763, P = 0.040) to analyze the data. However, no significant associations were found in Caucasians. This meta-analysis suggested that NQO1 C609T polymorphism most likely contributes to increased susceptibility to prostate cancer in the Asians. Further large-scale and well-designed case-control studies are necessary to validate the risk identified in the present meta-analysis.

Association between IRS-1 Gly972Arg polymorphism and colorectal cancer risk

In order to make a comprehensive assessment of the potential association between one genetic variant in the insulin receptor substrate 1 (IRS-1) gene, rs1801278, and colorectal cancer (CRC) risk, we conducted a meta-analysis of four epidemiological studies, which included 3,708 CRC cases and 4,176 controls. The data showed that rs1801278 polymorphism was not associated with increased CRC risk in the overall population. When stratifying by the race, the results showed that the rs1801278 polymorphism was associated with increased CRC risk under dominant model in mixed populations. Based on this meta-analysis, we conclude that the IRS-1 rs1801278 polymorphism might be a risk factor for CRC development in mixed populations. Further studies, either with larger sample size or involving other single nucleotide polymorphisms (SNPs) and haplotypes of the IRS-1 gene, are necessary to clarify the contribution of IRS-1 rs1801278 in colorectal carcinogenesis.

Lack of association between interleukin-4 -524C>T polymorphism and colorectal cancer susceptibility

Interleukin-4 (IL-4) -524C > T polymorphism has been implicated to alter the risk of colorectal cancer (CRC), but the results are controversial. The objective of this study was to quantitatively evaluate the association between IL-4 -524C > T polymorphism and CRC risk. A comprehensive search was conducted to identify all eligible studies of IL-4 -524C > T polymorphism and CRC risk. Statistical analysis was performed with Review Manager 5.0 and Stata 11. A total of 5 case-control studies, including 1,224 cases and 1,551 controls, were included. The combined results based on all eligible studies suggested that IL-4 -524C > T polymorphism was not associated with CRC susceptibility. When stratifying for race, the data showed that the IL-4 -524C > T polymorphism was also not associated with an increased CRC susceptibility in Caucasians. Our study suggests that IL-4 -524C > T polymorphism may be not associated with an increased CRC susceptibility.

The prognostic value of elevated ezrin in patients with osteosarcoma

Published studies researching the prognostic significance of ezrin expression in patients with osteosarcoma are inconclusive and heterogeneous. We conducted a meta-analysis to assess its prognostic value more precisely. The hazard ratios with corresponding 95 % confidence intervals were calculated to evaluate the effects. Five studies with 318 osteosarcoma patients were included to estimate the relationship between ezrin and disease-free survival, and ezrin and overall survival. Compared with osteosarcoma patients with low or negative ezrin expression, patients with high ezrin expression tended to be associated with lower disease-free survival, but the difference was not significant. However, patients with high ezrin expression were obviously associated with lower overall survival. Therefore, the findings from this systematic review suggest that ezrin expression is an effective biomarker of prognosis in patients with osteosarcoma.

SMAD7 rs12953717 polymorphism contributes to increased risk of colorectal cancer

Mothers against decapentaplegic homolog 7 (SMAD7) rs12953717 polymorphism has been implicated to alter the risk of colorectal cancer (CRC), but the results are controversial. The objective of this study was to quantitatively evaluate the association between SMAD7 rs12953717 polymorphism and CRC susceptibility. A comprehensive search was conducted to identify all eligible studies of SMAD7 rs12953717 polymorphism and CRC risk. Pooled odds ratio and 95% confidence interval were calculated using a fixed or random effects model. Statistical analysis was performed with Review Manager 5.0 and Stata 11. A total of 11 case-control studies, including 12,058 cases and 11,444 controls, were identified. The combined results based on all studies suggested that rs12953717 was associated with CRC risk under all genetic models. When stratifying for race, the data showed that the rs12953717 was associated with a significantly increased CRC risk under all genetic models in Caucasians. Statistically significant association was found in all genetic models except in recessive model comparison in the subgroup of Asians. After stratifying the studies by study design, there was a significant association between rs12953717 polymorphism and CRC risk under all genetic models in the subgroup of population-based studies. Our study suggests that rs12953717 polymorphism is associated with an increased CRC risk.