Vascular endothelial growth factor polymorphisms -1154 G/A and -460 C/T are not associated with VEGF mRNA expression and susceptibility to sporadic colon cancer

VEGF-2578C/A, -460T/C Polymorphisms and Gastrointestinal Tract Cancer Risk: An Updated Meta-Analysis

Functional polymorphisms in the vascular endothelial growth factor (VEGF) alter the susceptibility toward different gastrointestinal tract (GIT) cancers. In this study, we explored the association of VEGF-2578C/A and VEGF-460T/C polymorphisms with esophageal cancer (EC) risk. In total, 330 patients with EC and 330 controls for VEGF-2578C/A polymorphism and 316 patients with EC and 316 controls for VEGF-460T/C polymorphism were genotyped. AA genotype (p = 0.01) and A allele (p = 0.02) of VEGF-2578C/A and CC genotype (p = 0.04) and C allele (p = 0.04) of VEGF-460T/C polymorphism were significantly associated with an increased risk of EC. VEGF-2578C/A and VEGF-460T/C polymorphisms have been studied in different GIT cancers, but results are inconclusive. Therefore, we performed a meta-analysis to assess the association of these polymorphisms with the risk of GIT cancers. The PubMed, ScienceDirect, and Google Scholar databases were used to search the articles. Twenty-one studies on VEGF-2578C/A and 20 studies on VEGF-460T/C polymorphism were included in this meta-analysis. VEGF-2578C/A polymorphism was associated with the decreased risk of GIT cancer in the overall population under the overdominant model (p = 0.009). A significant association of VEGF-2578C/A polymorphism with GIT cancer risk has been observed in the middle easterners, Caucasians, and Asians under different genetic models. VEGF-460T/C polymorphism was significantly associated with an increased risk of GIT cancers in Caucasians. Stratification of the data on the basis of cancer type showed a significant association of VEGF-2578C/A polymorphism with the risk of gallbladder cancer, whereas VEGF-460T/C polymorphism was associated with the risk of hepatocellular cancer, gastric cancer, and colorectal cancer. Our meta-analysis suggested that VEGF-2578C/A and VEGF-460T/C polymorphisms were associated with GIT cancer risk.

The Significant Impacts of Interleukin-8 Genotypes on the Risk of Colorectal Cancer in Taiwan

Interleukin-8 (IL-8), a pro-inflammatory cytokine, is upregulated in CRC and plays an important role in its development and progression. Genetic variants in the IL-8 gene may impact the risk of CRC by modulating IL-8 levels. Our primary objective was to investigate the role of IL-8 genotypes in the development of CRC. To accomplish this, we employed the polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) method to analyze the genotypes of IL-8 rs4017, rs2227306, rs2227543, and rs1126647 in 362 CRC patients and 362 controls. Additionally, we evaluated the interactions between these genotypes and factors such as age, gender, smoking, alcohol consumption, and body mass index (BMI) status in relation to the risk of CRC. Furthermore, we utilized quantitative reverse transcription-PCR to measure the serum IL-8. The results demonstrated a significant difference in the distribution of rs4017 genotypes between the control and case groups (p for trend = 0.0059). Logistic regression analysis revealed that individuals with variant AA genotype had a 1.92-fold higher CRC risk (95% confidence interval [CI] = 1.28-2.89, p = 0.0023). Moreover, carriers of the IL-8 rs4017 AT + AA genotypes exhibited a significant association with CRC risk (odds ratio [OR] = 1.39, 95% CI = 1.02-1.91, p = 0.0460). Additionally, individuals with IL-8 rs4017 AA genotype displayed significantly elevated serum IL-8 compared to those with TT genotype at a 1.73-fold level (p < 0.0001), indicating a correlation between genotype and phenotype. In conclusion, the genotypes of IL-8 rs4017, along with their associated expression levels, can potentially serve as predictive markers for the risk of CRC.

The relationship between VEGF-460(T>C) polymorphism and cancer risk: A systematic review and meta-analysis based on 46 reports

BACKGROUND

Extensive studies on the link between single nucleotide polymorphisms (SNPs) in vascular endothelial growth factor (VEGF) and various malignancy risks produced conflicting results, notably for VEGF-460(T/C). To evaluate this correlation more comprehensively and accurately, we perform a meta-analysis.

METHODS

Through retrieving 5 databases (Web of Science (WoS), Embase, Pubmed, Wanfang database (Wangfang), and China National Knowledge Infrastructure (CNKI)) and applying hand search, citation search, and gray literature search, 44 papers included 46 reports were enrolled. To evaluate the relationship between VEGF-460 and cancer risk, we pooled odds ratios (ORs) and 95% confidence intervals (CIs).

RESULTS

Our results indicated that the VEGF-460 polymorphism is not related to malignancy susceptibility (dominant model, OR = 0.98, 95% CI = 0.87-1.09; recessive model, OR = 0.95, 95% CI = 0.82-1.10; heterozygous model, OR = 0.99, 95% CI = 0.90-1.10; homozygous model, OR = 0.92, 95% CI = 0.76-1.10; additive model, OR = 0.98, 95% CI = 0.90-1.07). While, in subgroup analysis, this SNP may reduce the risk of hepatocellular carcinoma.

CONCLUSION

this meta-analysis indicated that VEGF-460 was irrelevant to overall malignancy risk, but it might be a protective factor for hepatocellular carcinoma.

Impact of VEGFA promoter polymorphisms on esophageal cancer risk in North-West Indians: a case-control study

BACKGROUND

Angiogenesis play a critical role in the development and progression of tumors in solid tumors. Vascular endothelial growth factor (VEGF) is one of the most important endothelial cell mitogen which plays a critical role in normal physiological and tumor angiogenesis.

OBJECTIVES

The objective of this case-control study was to investigate the association of VEGF-2578C/A, -2549 I/D, and -460T/C promoter polymorphisms with esophageal cancer risk in North-West Indians.

METHODS

In this study, 200 sporadic esophageal cancer patients and 200 healthy, unrelated, age and gender matched controls were analyzed. The genomic DNA was extracted from blood samples using phenol chloroform method. Genotyping of VEGF- 2549I/D polymorphism was carried out by direct polymerase chain reaction (PCR) whereas VEGF -2578C/A and VEGF-460T/C) polymorphisms were analyzed by polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) method.

RESULTS

AA genotype (p = 0.005) and A allele (p = 0.005) VEGF -2578 C/A, II genotype (p = 0.011) and I allele (p = 0.012) of VEGF - 2549 I/D and CC genotype (p = 0.013) and C allele of VEGF-460T/C polymorphisms were significantly associated with increased risk of esophageal cancer. Stratification of data on the basis of gender showed that VEGF -2578 AA genotype (p = 0.001) and A allele (p = 0.001); VEGF -2549 II genotype (p = 0.002) and I allele (p = 0.002) and VEGF- 460CC genotype (p = 0.001) and C allele (p = 0.002) was significantly associated with increased risk of esophageal cancer in female group. Haplotype analysis revealed that A_-2578 I_- 2549 C_- 460 haplotype was significantly associated with increased risk for esophageal cancer in total samples (p = 0.008) as well as in female group (p = 0.001).

CONCLUSIONS

The results of present study indicate that VEGF -2578C/A, - 2549I/D and -460T/C polymorphisms were significantly associated with increased risk of esophageal cancer in North-West Indians.

Relationship between VEGF Gene Polymorphisms and Serum VEGF Protein Levels in Patients with Rheumatoid Arthritis

BACKGROUND

Rheumatoid arthritis (RA) is one of the chronic autoimmune diseases, with genetic and environmental predisposition, and synovial angiogenesis is considered to be a notable stage in its pathogenesis. Angiogenesis or vascular proliferation has been suggested to be a pivotal mechanism involved in both inflammation/immune activation and joint invasion and destruction. RA may be considered an "angiogenic disease" because it is associated with active tissue neovascularization. Vascular endothelial growth factor (VEGF) promotes vascular permeability, regulates angiogenesis, endothelial cell proliferation and migration, chemotaxis, and capillary hyper permeability and therefore is involved in the development of inflammation. VEGF is the most potent proangiogenic molecule promoting the angiogenic phenotype of RA and is upregulated in RA.

OBJECTIVES

The aim of the study was to identify functional VEGF variants and their possible association with VEGF expression, susceptibility to and severity of RA.

METHODS

581 RA patients and of 341 healthy individuals were examined for -1154 A/G, -2578 A/C VEGF gene polymorphisms by PCR-RFLP method and for -634 G/C VEGF gene polymorphisms by TaqMan SNP genotyping assay. Serum VEGF levels in RA patients and controls were measured by ELISA.

RESULTS

The -1154 A/G VEGF gene polymorphism under the codominant, recessive (AA+AG vs. GG) and dominant (AA vs. AG+GG) models were associated with RA (p = 0.0009; p = 0.004; p = 0.017, respectively). VEGF -2578 A/C revealed differences in the case-control distribution in codominant, recessive, dominant and overdominant models (all p<0.0001). Furthermore, the -634 G/C VEGF gene SNP was not correlated with susceptibility to RA in Polish population. The genotype-phenotype analysis showed significant association between the VEGF -1154 A/G and -634 G/C and mean value of the hemoglobin (all p = 0.05), additionally they relevated that the number of women with the polymorphic allele -2578 C was lower than the number of women with wild type allele -2578A (p = 0.006). Serum VEGF levels were significantly higher in RA patients than in control groups (both p = 0,0001).

CONCLUSION

Present findings indicated that VEGF genetic polymorphism as well as VEGF protein levels may be associated with the susceptibility to RA in the Polish population.

Significant effect of VEGFA polymorphisms on the clinical outcome of metastatic colorectal cancer patients treated with FOLFIRI-cetuximab

AIM

The efficacy of a cetuximab-based regimen used to treat metastatic colorectal cancer (mCRC) could be influenced by VEGFA polymorphisms.

MATERIALS & METHODS

We studied the effects of five polymorphisms in the VEGFA gene (-2549D/I, -1154G/A, -460T/C, +405G/C and +936C/T) on the outcome of 98 mCRC patients treated with FOLFIRI plus cetuximab.

RESULTS

Patients homozygous for the -2549D, -1154G and -460T alleles did exhibit higher response rates to treatment and longer progression-free survival compared with others. In addition, the DGTGC and IGCGC haplotypes were significantly associated with a lower risk of disease progression.

CONCLUSION

These findings suggest that VEGFA genetic variations might influence response/resistance of FOLFIRI plus cetuximab treatment in mCRC patients.

Association of VEGF and VEGFR1 polymorphisms with breast cancer risk in North Indians

The aim of present study was to evaluate the relationship between vascular endothelial growth factor (VEGF) -2578C/A, -2549I/D, -460T/C and -7C/T and VEGFR1 -710C/T polymorphisms with risk to breast cancer in North Indians. A total of 204 sporadic breast cancer patients and 204 controls were recruited for this case-control study. Significantly increased frequency of II genotype of -2549I/D polymorphism was observed in patients as compared to control individuals (odds ratio (OR) = 2.76, 95 % confidence interval (CI), 1.55-4.92; p = 0.0005). VEGF -2578AA genotype (OR = 2.87; 95 % CI, 1.61-5.10; p = 0.0003) and A allele (OR = 1.65, 95 % CI, 1.25-2.18; p = 0.0004) were found to be associated with increased risk for breast cancer. Individuals carrying CC genotype (OR = 2.23, 95 % CI, 1.25-3.97) and C allele (OR = 1.42, 95 % CI, 1.07-1.87) of VEGF -460T/C polymorphism were at higher risk of breast cancer. There was no significant difference in genotype and allele distribution of VEGF -7C/T and VEGFR1 -710C/T polymorphisms between cases and control individuals (p > 0.05). Linkage disequilibrium analysis showed a strong linkage between VEGF -2549I/D and -2578C/A polymorphisms (Lewontin's [Formula: see text] = 0.99; r (2) = 0.97), -2549I/D and -460T/C ([Formula: see text] = 0.94; r (2) = 0.84), and -2578C/A and -460T/C polymorphisms ([Formula: see text] = 0.93; r (2) = 0.83). In the present study, we concluded that VEGF -2549I/D, -2578C/A and -460T/C polymorphisms are associated with risk to breast cancer in Punjab, North India.

Vascular endothelial growth factor (VEGF) gene polymorphisms and breast cancer risk in Punjabi population from North West India

The purpose of this study was to evaluate the association of seven VEGF promoter polymorphisms with breast cancer risk in Punjabi population from North West India. We screened DNA samples of 102 sporadic breast cancer patients and 102 unrelated healthy, gender, and age-matched individuals for seven VEGF promoter polymorphisms [-417 C/T (rs833062), -172 C/A (rs59260042), -165 C/T (rs79469752), -160 C/T, -152 G/A (rs13207351), -141 A/C (rs28357093) and -116 G/A (rs1570360)] by direct sequencing. The frequency of GG, GA, and AA genotype of -152 G/A polymorphism was 26.47 vs 38.34%, 46.08 vs 51.96%, and 27.45 vs 9.80%, in patients and controls, respectively. VEGF -152 AA genotype was significantly associated with increased risk for breast cancer (OR = 4.04, 95%CI, 1.69-9.68, p = 0.001; recessive model OR = 3.48, 95%CI, 1.59-7.63, p = 0.001). For VEGF -116 G/A polymorphism, G and A allele frequencies were 65.2 vs 76.47% and 34.8 vs 23.53% in patients and controls, respectively. Individuals having -116 AA genotype (OR = 3.40; 95%CI, 1.24-9.37; p = 0.014) and A allele (OR = 1.73; 95%CI, 1.12-2.67; p = 0.012) were associated with increased risk for breast cancer. VEGF -165 C/T and -141 A/C polymorphisms were associated with reduced risk for breast cancer. There was significantly decreased frequency of CT genotype (4.90 vs 18.63%; p = 0.002) and T allele (2.45 vs 9.31%; p = 0.003) of -165 C/T polymorphism among breast cancer patients as compared to controls. VEGF -141 A and C allele frequency were 96.57 vs 91.18% and 3.43 vs 8.82% in patients and controls, respectively. Significant reduced risk for breast cancer was observed with AC genotype (OR = 0.34, 95%CI, 0.14-0.86; p = 0.019) and C allele (OR = 0.37; 95%CI, 0.15-0.89; p = 0.023) of -141 A/C polymorphism. We did not observe association of VEGF -417 T/C, -172 C/A, -160 C/T polymorphisms with breast cancer risk in the studied subjects (p > 0.05). The VEGF -152 G/A and -116 G/A polymorphisms were found to be significantly associated with increased risk for breast cancer while -165 C/T and -141 A/C polymorphisms were found to be associated with decreased risk for breast cancer in Punjabi population from North West India.

Personalizing colon cancer therapeutics: targeting old and new mechanisms of action

The use of pharmaceuticals for colon cancer treatment has been increasingly personalized, in part due to the development of new molecular tools. In this review, we discuss the old and new colon cancer chemotherapeutics, and the parameters that have been shown to be predictive of efficacy and safety of these chemotherapeutics. In addition, we discuss how alternate pharmaceuticals have been developed in light of a potential lack of response or resistance to a particular chemotherapeutic.

VEGFA, FLT1, KDR and colorectal cancer: assessment of disease risk, tumor molecular phenotype, and survival

Angiogenesis is essential for tumor progression. Vascular endothelial growth factor (VEGFA) and its receptors 1 (FLT1) and 2 (KDR), have been identified as major mediators of this process. We hypothesized that genetic variation in FLT1 (38 SNPs), KDR (22 SNPS), and VEGFA (11 SNPs) would be associated with colon and rectal cancer development and survival. Data from a case-control study of 1555 colon cancer cases and 1956 controls and 754 rectal cancer cases and 959 controls were used. An adaptive rank truncation product (ARTP), based on 10,000 permutations, was used to determine the statistical significance of the candidate genes and angiogenesis pathway. Based on ARTP results, FLT1 was significantly associated with risk of colon cancer (P(ARTP) = 0.045) and VEGFA was significantly associated with rectal cancer (P(ARTP) = 0.036). After stratifying by tumor molecular subtype, SNP associations observed for colon cancer were: VEGFA rs2010963 with CIMP+ colon tumors; FLT1 rs4771249 and rs7987649 with TP53; FLT1 rs3751397, rs7337610, rs7987649, and rs9513008 and KDR rs10020464, rs11941492, and rs12498529 with MSI+ and CIMP+/KRAS2-mutated tumors. FLT1 rs2296189 and rs600640 were associated with CIMP+ rectal tumors and FLT1 rs7983774 was associated with TP53-mutated rectal tumors. Four SNPs in FLT1 were associated with colon cancer survival while three SNPs in KDR were associated with survival after diagnosis with rectal cancer. Aspirin/NSAID use, smoking cigarettes, and BMI modified the associations. These findings suggest the importance of inflammation and angiogenesis in the etiology of colorectal cancer and that genetic and lifestyle factors may be targets for modulating disease risk.

Positive association of the vascular endothelial growth factor-A +405 GG genotype and poor survival in stage I-II gastric cancer in the Northern Chinese population

The vascular endothelial growth factor-A (VEGF-A) plays an important role in the angiogenesis and prognosis for gastric cancer. In addition, several single-nucleotide polymorphisms (SNPs) in VEGF-A have been shown to affect gene expression and process of angiogenesis. The present study evaluated the correlations between SNPs in VEGF-A and gastric cancer survival. Formalin-fixed paraffin-embedded tissues of 404 gastric cancer patients and blood samples from 404 controls were included in the study. The SNPs -460T/C (rs833061), +405G/C (rs2101963), -7C/T (rs25648) and +936C/T (rs3025039) were genotyped by matrix-assisted laser desorption/ionization time-of-flight mass spectrometry. We showed patients carrying the +405GG genotype had significantly worse survival in the N0 (lymph-node negative), N0L0 (lymph-node negative and lymphovascular-invasion negative) and TNM stage I-II subgroups (P = 0.021, P = 0.007 and P = 0.017, respectively). In addition, haplotype -460T/+405G/-7C and -460C/+405G/-7C carriers showed poor survival in the N0, N0L0 and TNM stage I-II subgroups (P = 0.004, P = 0.030 and P = 0.009 for TGC; P = 0.033, P = 0.049 and P = 0.011 for CGC). Overall, the +405 GG genotype or TGC and CGC haplotypes were correlated with poor survival in TNM stage I-II gastric cancer patients. The +405G/C polymorphism of VEGF-A could be used as a biomarker for molecular staging in stage I-II gastric cancer in Northern China.

Prognostic importance of VEGF-A haplotype combinations in a stage II colon cancer population

AIM

To investigate the prognostic effect of three VEGF-A SNPs, -2578, -460 and 405, as well as the corresponding haplotype combinations, in a unique population of stage II colon cancer patients.

PATIENTS & METHODS

The study included all patients diagnosed with stage II colon cancer in Denmark in 2003 (698 patients). One paraffin-embedded tissue block from each patient was used for DNA extraction and analysis of the three VEGF SNPs.

RESULTS

The homozygous genotype VEGF -2578 AA had significant effect on time to tumor recurrence (hazard ratio [HR] = 2.01 [95% CI: 1.13-3.56]; p = 0.02) as well as -460TT (HR = 0.50 [95% CI: 0.29-0.89]; p = 0.02). Patients harboring the haplotype combinations ACG,CTC and ACG,ACG displayed a significantly shorter time to tumor recurrence in both univariate (HR = 1.87 [95% CI: 1.21-2.89]; p = 0.008) and multivariate analysis (HR = 1.76 [95% CI: 1.09-2.82]; p = 0.02).

CONCLUSION

We found that the gene polymorphism in VEGF-A holds prognostic information and should be considered as a potential adjunct in identification of high-risk stage II colon cancer patients.

Association of VEGF and KDR single nucleotide polymorphisms with colorectal cancer susceptibility in Koreans

Vascular endothelial growth factor (VEGF) and its receptor kinase insert domain-containing receptor (KDR) play crucial roles in angiogenesis, which contributes to the development and progression of solid tumors. The aim of this study was to investigate the associations of VEGF (-2578C > A, -1154G > A, -634G > C, and 936C > T) and KDR (-604T > C and 1192G > A) polymorphisms with the development of colorectal cancer (CRC). A total of 882 participants (390 CRC patients and 492 controls) were enrolled in the study. The genotyping of VEGF and KDR polymorphisms was performed by polymerase chain reaction-restriction fragment length polymorphism assay. We found that the CT and TT genotype of the 936C > T was associated with an increased risk of CRC compared with the CC genotype as the dominant model for the T allele. In addition, we also found a increased CRC risk with TC + CC genotype of KDR -604T > C compared with TT genotype in CRC patients and control subjects. Similarly, KDR 1192G > A also showed significant association between 1192G > A variants and risk of CRC. In the haplotype analyses, haplotype -2578A/-1154A/-634G/936T of VEGF polymorphisms and haplotype -604C/1192G and -604C/1192A of KDR polymorphisms were associated with an increased susceptibility of CRC. Our results suggest that the VEGF 936C > T, KDR -604T > C, and KDR 1192G > A polymorphisms may be contribute to CRC risk in the Korean population.

Vascular endothelial growth factor (VEGF) gene polymorphisms and colorectal cancer: a meta-analysis of epidemiologic studies

BACKGROUND

Studies investigating the association between vascular endothelial growth factor (VEGF) polymorphisms and colorectal cancer (CRC) risk report conflicting results. To clarify the effect of four VEGF (-460T/C, -634G/C, +936C/T, and -2578C/A) gene polymorphisms on the risk of developing CRC, we carried out a meta-analysis using published data to obtain more precise estimates of risk.

METHODS

Electronic searches of PubMed and EMBASE were conducted to select studies for this meta-analysis. The principal outcome measure was the odds ratio (OR) with 95% confidence interval (CI) for the risk of CRC associated with four VEGF (-460T/C, -634G/C, +936C/T, and -2578C/A) gene polymorphisms.

RESULTS

We identified 12 epidemiologic studies, which included 2770 CRC cases and 2568 controls. The combined results based on all studies showed that CRC cases had a significantly higher frequency of VEGF -634GG (OR=1.24, 95% CI=1.06, 1.44) and -2578AA (OR=1.37, 95% CI=1.12, 1.66) genotype and a lower frequency of -634CG (OR=0.82, 95% CI=0.71, 0.95) than controls. When stratifying for race, we found that patients with CRC had a significantly higher frequency of -460TC (OR=1.54, 95% CI=1.22, 1.94), -460CC (OR=2.00, 95% CI=1.50, 2.67), and -2578AA (OR=1.38, 95% CI=1.12, 1.69) and a lower frequency of -2578AA (OR=0.78, 95% CI=0.65, 0.93) genotypes of VEGF than controls, among Caucasians. We also found that patients with CRC had a significantly higher frequency of -634GG (OR=1.61, 95% CI=1.20, 2.15) and a lower frequency of -634CG (OR=0.60, 95% CI=0.46, 0.79) genotypes of VEGF than controls, among Asians.

CONCLUSIONS

Our meta-analysis suggests that the VEGF -460T/C, -634G/C, and -2578C/A gene polymorphisms are associated with a risk of CRC.

Association between kinase insert domain-containing receptor gene polymorphisms and silent brain infarction: a Korean study

BACKGROUND

Kinase insert domain-containing receptor (KDR), vascular endothelial growth factor receptor-2, play a pivotal role in endothelial dysfunction, which may lead to silent brain infarction (SBI). We evaluated whether single nucleotide polymorphisms (SNPs) of KDR genes are associated with increased risk of SBI in a Korean population.

METHODS

A total of 383 patients with SBI and 387 controls were genotyped for the KDR -604T>C, 1192G>A, and 1719A>T SNPs. We separately analyzed this association according to the age (age≥65 and age<65) and the gender. We also compared haplotype frequencies between SBI patients and controls.

RESULTS

Genotype frequencies for three SNPs did not differ significantly between SBI patients and controls. In addition, haplotype analysis for three SNPs did not show a difference between patients and controls. However, the frequency of genotype of KDR -604T>C was significantly associated with an increased risk of SBI in the age<65 years old group (AOR=1.515, 95% CI, 1.003 to 2.289, p=0.048) and in male group (AOR=1.596, 95% CI, 1.018 to 2.503, p=0.042).

CONCLUSIONS

KDR -604T>C SNP may serve as genetic markers for the increased risk of SBI among the younger (<65 years) or male only Korean subpopulations.

Clinical implications of genetic variations in the VEGF system in relation to colorectal cancer

Colorectal cancer (CRC) constitutes one of the most common malignancies in the world and, despite advances in diagnostics and treatments, patients still face a poor prognosis and a more individualized treatment approach appears necessary. The VEGF system and angiogenesis are involved in many aspects of tumor biology and the efficacy of chemotherapy, and some targeted therapeutics appear to be related to the function of these processes. There are many reasons why genetic variations are optimal biomarkers and in relation to the VEGF system may prove to be of clinical relevance. This review evaluates the literature on SNPs in relation to the risk of CRC and the possible prognostic and predictive value and argues for the role of these biomarkers in the future treatment of patients with CRC.

Identification of cis- and trans-acting genetic variants explaining up to half the variation in circulating vascular endothelial growth factor levels

RATIONALE

Vascular endothelial growth factor (VEGF) affects angiogenesis, atherosclerosis, and cancer. Although the heritability of circulating VEGF levels is high, little is known about its genetic underpinnings.

OBJECTIVE

Our aim was to identify genetic variants associated with circulating VEGF levels, using an unbiased genome-wide approach, and to explore their functional significance with gene expression and pathway analysis.

METHODS AND RESULTS

We undertook a genome-wide association study of serum VEGF levels in 3527 participants of the Framingham Heart Study, with preplanned replication in 1727 participants from 2 independent samples, the STANISLAS Family Study and the Prospective Investigation of the Vasculature in Uppsala Seniors study. One hundred forty single nucleotide polymorphism (SNPs) reached genome-wide significance (P<5×10(-8)). We found evidence of replication for the most significant associations in both replication datasets. In a conditional genome-wide association study, 4 SNPs mapping to 3 chromosomal regions were independently associated with circulating VEGF levels: rs6921438 and rs4416670 (6p21.1, P=6.11×10(-506) and P=1.47×10(-12)), rs6993770 (8q23.1, P=2.50×10(-16)), and rs10738760 (9p24.2, P=1.96×10(-34)). A genetic score including these 4 SNPs explained 48% of the heritability of serum VEGF levels. Six of the SNPs that reached genome-wide significance in the genome-wide association study were significantly associated with VEGF messenger RNA levels in peripheral blood mononuclear cells. Ingenuity pathway analyses showed found plausible biological links between VEGF and 2 novel genes in these loci (ZFPM2 and VLDLR).

CONCLUSIONS

Genetic variants explaining up to half the heritability of serum VEGF levels were identified. These new insights provide important clues to the pathways regulating circulating VEGF levels.

Single nucleotide polymorphisms of the vascular endothelial growth factor gene associated with incidence of oral squamous cell carcinoma

BACKGROUND

  Vascular endothelial growth factor (VEGF) plays an important role in promoting angiogenesis and is overexpressed in several malignancies. Polymorphisms of the VEGF gene can alter VEGF protein expression, which may be biologically significant and account for heterogeneity in disease risk and outcome. The aim of this case-control study was to evaluate potential associations between single nucleotide polymorphisms (SNP) of the VEGF gene with susceptibility of oral squamous cell carcinoma (OSCC).

PATIENTS AND METHODS

Five VEGF SNP (-1154 G/A, +405 G/C, +936 C/T, -2578 C/A and -460 C/T) were determined in peripheral blood isolated from 80 patients with OSCC and from 40 age- and gender-matched healthy volunteers (RT-PCR).

RESULTS

The +936 T allele and the -2578 C/A SNP were expressed significantly more often in the OSCC-group (P=0.002; P<0.0001) where three associations between two SNPs (+936 and +405, -2578 and -1154, -460 and -2578) were found.

CONCLUSION

Our findings provide support that +936 T allele and -2578 C/A SNP of the VEGF gene alone or in combination with other SNP are associated with OSCC. The SNPs may be used as biomarker for the development of specialized anti-VEGF drugs. Further studies must confirm the value of preoperative genetic analysis for prognosis.

Pharmacodynamic and pharmacogenetic angiogenesis-related markers of first-line FOLFOXIRI plus bevacizumab schedule in metastatic colorectal cancer

Background:

The identification of molecular and genetic markers to predict or monitor the efficacy of bevacizumab (BV) represents a key issue in the treatment of metastatic colorectal cancer (mCRC).

Methods:

Plasma levels of vascular endothelial growth factor (VEGF), placental growth factor (PlGF), soluble VEGF receptor 2 (sVEGFR-2) and thrombospondin-1 (TSP-1) were assessed by ELISA assay at different time points in a cohort of 25 patients enroled in a phase II trial of GONO-FOLFOXIRI plus BV as first-line treatment of mCRC. VEGF: −2578A/C, −1498C/T, −1154A/G, −634C/G and 936C/T; and VEGFR-2: −604A/G, +1192C/T and +1719A/T, polymorphisms were assessed in a total of 54 patients.

Results:

Treatment with GONO-FOLFOXIRI plus BV determined a prolonged and significant reduction in plasma free, biologically active VEGF concentration. Interestingly, VEGF concentrations remained lower than at baseline also at the time of PD. Conversely, PlGF levels increased during the treatment if compared with baseline, suggesting a possible role in tumour resistance; moreover, sVEGFR-2 increased at the time of PD, as well as TSP-1. No association of assessed polymorphisms with outcome was found.

Conclusion:

Our study suggested the possible mechanisms of resistance to combined therapy in those patients with a progressive disease to be tested in ongoing phase III randomised studies.

Association of vascular endothelial growth factor gene polymorphisms with susceptibility to epithelial ovarian cancer

BACKGROUND

Vascular endothelial growth factor (VEGF) is a major angiogenic factor involved in a number of pathological processes, including neovascularization, a crucial step in the development of solid malignancies. The aim of this study was to investigate the association of polymorphisms in the VEGF gene with susceptibility to epithelial ovarian cancer (EOC).

METHODS

This case-control study included 303 EOC patients and 303 healthy controls. Genotyping of the VEGF gene polymorphisms at j460C/T, j1154G/A, j2578C/A, and +936C/T were performed by polymerase chain reaction and restriction fragment length polymorphism analysis.

RESULTS

No significant difference was found in allele and genotype distributions of the -460C/T, +936C/T, and -2578C/A polymorphisms between patients and controls. However, the frequencies of -1154G/A genotype and allele were significantly different between the two groups (P = 0.037, P = 0.013). Compared with the G/A + A/A genotype, the G/G genotype could significantly increase the risk of developing EOC (odds ratio, 1.64; 95% confidence interval, 1.12Y2.39). The haplotype analysis suggested that the -460T/ -1154A/ -2578C haplotype exhibited a decrease in the risk of developing EOC compared with the -460T/ -1154G/ -2578C haplotype (odds ratio, 0.644; 95% confidence interval, 0.415-0.999).

CONCLUSIONS

The study suggested a possible association between the VEGF -1154G/A polymorphism with susceptibility to EOC, but there is no support for an association of the VEGF -460C/T, +936C/T, and -2578C/A polymorphisms with the risk for EOC.

Vascular endothelial growth factor 1498C/T, 936C/T polymorphisms associated with increased risk of colorectal adenoma: a Chinese case-control study

Single nucleotide polymorphisms in vascular endothelial growth factor gene VEGF, 1498C/T and 936 C/T are associated with colorectal cancer. We sought to determine whether such genetic variability in VEGF contributes to susceptibility of colorectal adenoma (CRA), a presumably precancerous state of colorectal cancer. In this research, two aforementioned polymorphisms were investigated for CRA susceptibility in a Chinese case-control study. The epidemiological risk factors were collected through questionnaire. The plasma VEGF levels were measured via enzyme-linked immunosorbent assay (ELISA). The Taqman-Probe assay was used to determine genotypes in 224 CRA patients and 200 CRA-free controls. The clinicopathological data of each sample were collected for further correlation analysis. According to data analysis males, cigarette smokers, patients who carry metabolic syndrome or familial antecedent of adenomas were significantly associated with CRA risk. Plasma VEGF levels of CRA patients were higher than those of controls (P = 0.003). This difference is independent of genotypes. The carriers with 936CT and CT+TT had higher risk of CRA in comparison with controls (CT vs. CC, OR 2.00, 95% CI 1.23-3.25, P = 0.006; CT+TT vs. CC, OR 2.04, 95% CI 1.28-3.26, P = 0.003). 936-T allele was associated with increased risk of CRA (OR 1.91, 95% CI 1.25-2.91, P = 0.003). Both CRA and control show no difference in the genotype of 1498C/T and the allele frequency of C-/T-. CRA patients with haplotype 1498T+936T presented significantly higher risk than those with wild-type 1498T+936C. Moreover, patients carrying 936CT+TT and 936-T allele demonstrated a tendency for villous adenoma. CRA patients have elevated plasma VEGF levels. The VEGF 936C/T polymorphism and 1498T+936T haplotype were found to be associated with increased CRA susceptibility.

Vascular endothelial growth factor polymorphisms: role in response and toxicity of tyrosine kinase inhibitors

Angiogenesis is central to the growth of normal tissues and tumors. Inhibiting this pathway has been a strategy for drug development for tumors not responsive to most agents used in chemotherapy. Notably, signaling mediated by vascular endothelial growth factor (VEGF) is a key target because aberrant signaling via this pathway is frequently associated with neoangiogenesis in tumors. The drug-discovery effort to blunt VEGF signaling has led to the approval of bevacizumab and several receptor tyrosine kinase inhibitors (TKIs) that have shown efficacy in the clinical management of breast, colorectal, lung, and kidney cancer. Understanding the genetic variability in VEGF and VEGF receptor has led to identifying genotypic variations (single nucleotide polymorphisms [SNPs]) associated with treatment outcome and toxicity. Notably, identification of SNPs in VEGF associated with angiogenesis inhibitor treatment-induced hypertension and outcome provides exciting opportunities for personalized medicine to improve outcome and reduced toxicity with these novel TKIs.

The prognostic value of haplotypes in the vascular endothelial growth factor a gene in colorectal cancer

New prognostic markers in patients with colorectal cancer (CRC) are a prerequisite for individualized treatment. Prognostic importance of single nucleotide polymorphisms (SNPs) in the vascular endothelial growth factor A (VEGF-A) gene has been proposed. The objective of the present study was to investigate the prognostic importance of haplotypes in the VEGF-A gene in patients with CRC. The study included 486 patients surgically resected for stage II and III CRC, divided into two independent cohorts. Three SNPs in the VEGF-A gene were analyzed by polymerase chain reaction. Haplotypes were estimated using the PHASE program. The prognostic influence was evaluated using Kaplan-Meir plots and log rank tests. Cox regression method was used to analyze the independent prognostic importance of different markers. All three SNPs were significantly related to survival. A haplotype combination, responsible for this effect, was present in approximately 30% of the patients and demonstrated a significant relationship with poor survival, and it remained an independent prognostic marker after multivariate analysis, hazard ratio 2.46 (95% confidence interval 1.49–4.06), p < 0.001. Validation was provided by consistent findings in a second and independent cohort. Haplotype combinations call for further investigation.

VEGF -460T → C polymorphism and its association with VEGF expression and outcome to FOLFOX-4 treatment in patients with colorectal carcinoma

The -460T → C polymorphism of vascular endothelial growth factor (VEGF) gene significantly increases its promoter activity. A pilot study was conducted to assess the influence of this polymorphism on clinicopathological features of patients with colorectal carcinoma. In total, 228 patients were enrolled, including 100 with stage II/III colorectal carcinoma receiving curative surgery and 128 with metastatic disease. An excellent correlation in VEGF -460 genotypes based on white blood cells and tumor tissues existed, but there was no between-group difference in patients with or without colorectal carcinoma. A marked increase in intratumor and circulating VEGF levels were observed in patients with the T/C or C/C genotypes (P < 0.01), which was associated with increased extent of invasion, nodal involvement, poor histological differentiation, subsequent metastasis and shorter survival in stage II/III patients treated with curative surgery (P < 0.01). For patients with metastatic disease, this polymorphism was associated with a lower response rate to FOLFOX-4 (P = 0.03) and shorter survival (P < 0.001). By multivariate analysis, this polymorphism was identified as an independent prognostic factor (P = 0.01). These data suggest that -460T → C polymorphism of VEGF gene, by increasing VEGF expression and subsequent angiogenesis, could be a key determinant for increased tumor recurrence and a poor prognosis of patients with colorectal carcinoma. However, this study is exploratory and is not adjusted for multiple comparisons, requiring independent replication.

The predictive value of genetic variations in the vascular endothelial growth factor A gene in metastatic colorectal cancer

Single-nucleotide polymorphisms (SNPs) in the vascular endothelial growth factor A (VEGF-A) gene may have clinical implications. The aim of this study was to investigate the possible predictive value of the VEGF-A SNPs, in patients with metastatic colorectal cancer (mCRC) treated with first-line capecitabine and oxaliplatin (XELOX). The study included 72 patients with mCRC. Genomic DNA was isolated from whole blood, and SNPs were analyzed by PCR. SNPs were correlated with response and progression-free survival (PFS). Haplotypes were estimated using the PHASE program. Response was observed in 21% of the patients with the -2578 CA genotype compared with 59% of the patients with CC+AA, P=0.002, in 26% of the patients with the -460 CT genotype compared with 57% with CC+TT, P=0.01, and in 27% of the patients with the +405 GC genotype compared with 54% with GG+CC, P=0.02. Two SNPs were significantly related to PFS. A haplotype with a significant relationship to response was identified. The results demonstrated obvious relationships between genetic variations in the VEGF-A gene and response to first-line XELOX in patients with mCRC, which translated to a significant difference in PFS. The results call for validation in a larger cohort of patients.

VEGF -460C>T polymorphism and cancer risk: a meta-analysis

Vascular endothelial growth factor (VEGF) is a major driver of physiological and pathological angiogenesis and plays important roles in the etiology and metastasis of cancers. The -460C>T polymorphism in VEGF gene region has been implicated in cancer risk and related to VEGF expression. However, published data remain conflicting. To derive a more precise estimation, a meta-analysis of 5,863 cases and 5,276 controls from 14 published case-control studies was performed. Odds ratios (ORs) with 95% confidence intervals (CIs) were estimated to assess the association. VEGF -460T represented a risk factor for cancers in Asians (OR=1.69, 95% CI: 1.09-2.62) but not in Europeans (OR=0.92, 95% CI: 0.78-1.08). Our meta-analysis showed the evidence that VEGF -460T was associated with increased cancer risk in Asians. Further prospective researches with larger numbers of worldwide participants are expected to validate this result.