Interethnic Differences in the Distribution of Clinically Relevant Vascular Endothelial Growth Factor Genetic Polymorphisms

Associations of Genetically Predicted Lp(a) (Lipoprotein [a]) Levels With Cardiovascular Traits in Individuals of European and African Ancestry

BACKGROUND

Lp(a) (lipoprotein [a]) levels are higher in individuals of African ancestry (AA) than in individuals of European ancestry (EA). We examined associations of genetically predicted Lp(a) levels with (1) atherosclerotic cardiovascular disease subtypes: coronary heart disease, cerebrovascular disease, peripheral artery disease, and abdominal aortic aneurysm and (2) nonatherosclerotic cardiovascular disease phenotypes, stratified by ancestry.

METHODS

We performed (1) Mendelian randomization analyses for previously reported cardiovascular associations and (2) Mendelian randomization-phenome-wide association analyses for novel associations. Analyses were stratified by ancestry in electronic Medical Records and Genomics, United Kingdom Biobank, and Million Veteran Program cohorts separately and in a combined cohort of 804 507 EA and 103 580 AA participants.

RESULTS

In Mendelian randomization analyses using the combined cohort, a 1-SD genetic increase in Lp(a) level was associated with atherosclerotic cardiovascular disease subtypes in EA-odds ratio and 95% CI for coronary heart disease 1.28 (1.16-1.41); cerebrovascular disease 1.14 (1.07-1.21); peripheral artery disease 1.22 (1.11-1.34); abdominal aortic aneurysm 1.28 (1.17-1.40); in AA, the effect estimate was lower than in EA and nonsignificant for coronary heart disease 1.11 (0.99-1.24) and cerebrovascular disease 1.06 (0.99-1.14) but similar for peripheral artery disease 1.16 (1.01-1.33) and abdominal aortic aneurysm 1.34 (1.11-1.62). In EA, a 1-SD genetic increase in Lp(a) level was associated with aortic valve disorders 1.34 (1.10-1.62), mitral valve disorders 1.18 (1.09-1.27), congestive heart failure 1.12 (1.05-1.19), and chronic kidney disease 1.07 (1.01-1.14). In AA, no significant associations were noted for aortic valve disorders 1.08 (0.94-1.25), mitral valve disorders 1.02 (0.89-1.16), congestive heart failure 1.02 (0.95-1.10), or chronic kidney disease 1.05 (0.99-1.12). Mendelian randomization-phenome-wide association analyses identified novel associations in EA with arterial thromboembolic disease, nonaortic aneurysmal disease, atrial fibrillation, cardiac conduction disorders, and hypertension.

CONCLUSIONS

Many cardiovascular associations of genetically increased Lp(a) that were significant in EA were not significant in AA. Lp(a) was associated with atherosclerotic cardiovascular disease in four major arterial beds in EA but only with peripheral artery disease and abdominal aortic aneurysm in AA. Additionally, novel cardiovascular associations were detected in EA.

Preserved endothelial progenitor cell angiogenic activity in African American essential hypertensive patients

Background

African American (AA) subjects with essential hypertension (EH) have greater inflammation and cardiovascular complications than Caucasian EH. An impaired endogenous cellular repair system may exacerbate vascular injury in hypertension, yet whether these differ between AA EH and Caucasian EH remains unknown. Vascular repair by circulating endothelial progenitor cells (EPCs) is controlled by regulators of EPC mobilization, homing, adhesion and new vessel formation, but can be hindered by various cytokines. We hypothesized that EPC levels and function would be impaired in AA EH compared with Caucasian EH, in association with increased levels of inflammatory mediators and EPC regulators.

Methods

CD34+/KDR+ EPCs were isolated from inferior vena cava and renal vein blood samples of AA EH and Caucasian EH patients (n = 18 each) and from peripheral veins of 17 healthy volunteers (HVs) and enumerated using fluorescence-activated cell sorting. Angiogenic function of late-outgrowth endothelial cells expanded from these samples for 3 weeks was tested in vitro. Levels of inflammatory mediators, angiogenic factors and EPC regulators were measured by Luminex.

Results

EPC levels were decreased in both AA and Caucasian EH compared with HVs, whereas their late-outgrowth endothelial cell angiogenic function was comparable. Levels of several inflammatory mediators were elevated in AA EH compared with Caucasian EH and HVs. Contrarily, vascular endothelial growth factor and its receptor-2 were lower. EPC levels inversely correlated with blood pressure in all hypertensive patients and estimated glomerular filtration rate with inflammatory mediators only in AA EH.

Conclusions

Despite lower EPC numbers, decreased vascular endothelial growth factor signaling and inflammation, EPC function is preserved in AA EH compared with Caucasian EH and HVs, suggesting compensatory mechanisms for vascular repair.

Genetic Variants in Preeclampsia: Lessons From Studies in Latin-American Populations

Placental vascularization is a tightly regulated physiological process in which the maternal immune system plays a fundamental role. Vascularization of the maternal-placental interface involves a wide range of mechanisms primarily orchestrated by the fetal extravillous trophoblast and maternal immune cells. In a healthy pregnancy, an immune cross-talk between the mother and fetal cells results in the secretion of immunomodulatory mediators, apoptosis of specific cells, cellular differentiation/proliferation, angiogenesis, and vasculogenesis, altogether favoring a suitable microenvironment for the developing embryo. In the context of vasculopathy underlying common pregnancy disorders, it is believed that inefficient invasion of extravillous trophoblast cells in the endometrium leads to a poor placental blood supply, which, in turn, leads to decreased secretion of angiogenic factors, hypoxia, and inflammation commonly associated with preterm delivery, intrauterine growth restriction, and preeclampsia. In this review, we will focus on studies published by Latin American research groups, providing an extensive review of the role of genetic variants from candidate genes involved in a broad spectrum of biological processes underlying the pathophysiology of preeclampsia. In addition, we will discuss how these studies contribute to fill gaps in the current understanding of preeclampsia. Finally, we discuss some trending topics from important fields associated with pregnancy vascular disorders (e.g., epigenetics, transplantation biology, and non-coding RNAs) and underscore their possible implications in the pathophysiology of preeclampsia. As a result, these efforts are expected to give an overview of the extent of scientific research produced in Latin America and encourage multicentric collaborations by highlighted regional research groups involved in preeclampsia investigation.

Angiogenesis and oxidative stress-related gene variants in recurrent pregnancy loss

Recurrent pregnancy loss (RPL) affects ~3-5% of couples attempting to conceive and in around 50% of cases the aetiology remains unknown. Adequate vascularisation and placental circulation are indispensable for the development of a normal pregnancy. Prostaglandin-endoperoxide synthase 2 (PTGS2), vascular endothelial growth factor (VEGF) and the nitric oxide (NO) systems play important roles in reproductive physiology, participating in several steps including implantation and apoptosis of trophoblast cells. In this study we evaluated genetic polymorphisms in the inducible nitric oxide synthase (NOS2), PTGS2 and VEGFA genes as susceptibility factors for RPL. A case-control study was conducted in 149 women having two or more miscarriages and 208 controls. Allele and genotype distributions of the polymorphisms studied in the two groups were not statistically different. However, the dominant model showed that the presence of variant T (TT/GT) of rs2779249 (-1290G>T) of NOS2 was significantly associated with RPL (OR=1.58, CI 95%=1.03-2.44; P=0.037). The increased risk remained significant when adjusted for number of pregnancies, alcohol consumption and ethnicity (OR=1.92, CI95%=1.18-3.11; P=0.008). These results suggest that the variant genotypes of the functional polymorphism rs2779249 in the NOS2 promoter are a potential risk for RPL, possibly due to oxidative stress mechanisms.

Ethnic differences in the +405 and -460 vascular endothelial growth factor polymorphisms and peripheral neuropathy in patients with diabetes residing in a North London, community in the United Kingdom

BACKGROUND

There are marked ethnic differences in the susceptibility to the long-term diabetic vascular complications including sensory neuropathy. The vascular endothelial growth factor (VEGF) +405 (C/G) and -460 (T/C) polymorphisms are associated with retinopathy and possibly with nephropathy, however no information is available on their relationship with peripheral neuropathy. Therefore, we examined the prevalence of these VEGF genotypes in a multi-ethnic cohort of patients with diabetes and their relationship with evident peripheral diabetic neuropathy.

METHODS

In the current investigation, we studied 313 patients with diabetes mellitus of African-Caribbean, Indo-Asian and Caucasian ethnic origin residing in an inner-city community in London, United Kingdom attending a single secondary care centre. Genotyping was performed for the VEGF +405 and VEGF -460 polymorphisms using a pyrosequencing technique.

RESULTS

Forty-nine patients (15.6%) had clinical evidence of peripheral neuropathy. Compared to Caucasian patients, African-Caribbean and Indo-Asian patients had lower incidence of neuropathy (24.6%, 14.28%, 6.7%, respectively; P = 0.04). The frequency of the VEGF +405 GG genotype was more common in Indo-Asian patients compared to African-Caribbean and Caucasian patients (67.5%, 45.3%, 38.4%, respectively; p ≤ 0.02). The G allele was more common in patients with type 2 diabetes of Indo-Asian origin compared to African-Caribbean and Caucasian origin (p ≤ 0.02). There was no difference between the ethnic groups in VEGF -460 genotypes. The distributions of the VEGF +405 and VEGF -460 genotypes were similar between the diabetic patients with and without neuropathy.

CONCLUSIONS

In this cohort of patients, VEGF +405 and VEGF -460 polymorphisms were not associated with evident diabetic peripheral neuropathy, however an association was found between VEGF +405 genotypes and Indo-Asian which might have relevance to their lower rates of ulceration and amputation. This finding highlights the need for further investigation of any possible relationship between VEGF genotype, circulating VEGF concentrations and differential vulnerability to peripheral neuropathy amongst diabetic patients of different ethnic backgrounds.

Polymorphisms in VEGFA gene affect the antihypertensive responses to enalapril

PURPOSE

Vascular endothelial growth factor (VEGF) is a potent angiogenic factor that affects blood pressure by promoting vasodilation mediated by nitric oxide. Angiotensin-converting enzyme inhibitors (ACEi) up-regulate the VEGF expression; thus, genetic polymorphisms in the VEGFA gene could affect the antihypertensive responses to these drugs.

METHODS

Hypertensive patients (n = 102) were prospectively treated only with the ACEi enalapril for 60 days. We compared the effect of VEGFA polymorphisms on changes in blood pressure after enalapril treatment. In addition, multiple linear regression analysis was carried out to assess the effect of covariates on blood pressure. Genotypes for g.-2578C>A (rs699947), g.-1154G>A (rs1570360), and g.-634G>C (rs2010963) VEGFA polymorphisms were determined, and haplotype frequencies were estimated.

RESULTS

Individuals carrying the CA and AA genotypes for the g.-2578C>A polymorphism and the AGG haplotype showed more intense decrease in blood pressure in response to enalapril 20 mg/day. A multiple linear regression analysis showed that the AA genotype for the g.-2578C>A polymorphism and the AGG haplotype are associated with more intense decrease in blood pressure in response to enalapril 20 mg/day, while the CC genotype for the g.-2578C>A polymorphism and the CGG haplotype are associated with the opposite effect.

CONCLUSIONS

These findings suggest that polymorphisms in VEGFA gene may affect the antihypertensive responses to enalapril.

Association between the polymorphisms of the vascular endothelial growth factor gene and metabolic syndrome

Vascular endothelial growth factor (VEGF) is a major angiogenic factor. Increased levels of VEGF have been reported in patients with metabolic syndrome (MetS). The role of VEGF polymorphisms in MetS susceptibility, however, has not been reported previously. Thus, the present study was performed to analyze the associations between the VEGF -634G>C and 936C>T polymorphisms and the patients with MetS. A total of 320 patients with MetS (mean age, 49.86±11.76 years) and 320 healthy subjects (mean age, 50.94±8.43 years) were enrolled in the study. The VEGF -634G>C polymorphism in the 5'-untranslated region (UTR) and 936C>T polymorphism in 3'-UTR were analyzed by polymerase chain reaction-restriction fragment length polymorphism. The VEGF -634G>C polymorphism significantly affected MetS susceptibility. The CC genotype of the -634G>C polymorphism was significantly associated with an increased risk of MetS [adjusted odds ratio (AOR)=3.973; 95% confidence interval (CI), 2.321-6.799; P<0.0001]. AORs of the dominant (GG vs. GC+CC) and recessive models (GG+GC vs. CC) between the cases and controls were 2.569 (95% CI, 1.657-3.983; P<0.0001) and 2.163 (95% CI, 1.475-3.171; P=0.0001), respectively. Haplotypes of -634G>C and 936C>T were also associated with MetS susceptibility. When the haplotype data were stratified by gender, the association remained only in males. The -634G>C polymorphism was also associated with the subgroups of MetS risk components by the stratification analysis. The 936C>T polymorphism was, however, not associated with the MetS susceptibility. The present study demonstrates that the VEGF -634G>C polymorphism and haplotypes may be a genetic determinant for the MetS susceptibility. To the best of our knowledge, this is the first study on the significant association of the VEGF polymorphisms in MetS patients. To confirm the effects of the VEGF polymorphisms on MetS, further functional and population studies are required.

Role of vascular endothelial growth factor polymorphisms (-2578C>A, -460 T>C, -1154G>A, +405G>C and +936C>T) in endometriosis: a case-control study with Brazilians

Background

Endometriosis is regarded as a complex and heterogeneous disease in which genetic and environmental factors contribute to the phenotype. The Vascular Endothelial Growth Factor (VEGF) plays important roles in the pathogenesis of endometriosis. The present study was aimed at investigating the contribution of VEGF polymorphisms as risk factors for the development of endometriosis. This is the first study to evaluate the combined influence of the five most common VEGF polymorphisms.

Methods

This study was conducted at two hospitals from the Brazilian public health system, and comprised 294 women submitted to laparoscopic or laparotomy surgery: 182 patients had a histologically confirmed diagnosis of endometriosis (cases), whereas 112 had no evidence of the disease (controls). The VEGF polymorphisms were determined by TaqMan real-time polymerase chain reaction. The odds ratio (OR) with their 95% confidence intervals (CI) were calculated using an unconditional logistic regression model.

Results

Endometriosis patients and controls did not differ regarding age distribution, whereas the body mass index was significantly lower in endometriosis patients, when compared with controls (23.1 ± 3.9 versus 27.3 ± 5.9, P < 0.001). The evaluation of gynecological symptoms, including dysmenorrhea, non-cyclic chronic pelvic pain, dyspareunia and infertility, indicates significantly higher prevalences among endometriosis cases. The variant allele -1154A was significantly associated with endometriosis, either considering all cases (OR: 1.90, 95% CI: 1.23–2.97), deep infiltrating endometriosis (DIE) (OR: 1.83, 95% CI: 1.16-2.90) or moderate and severe endometriosis (stages III-IV) (OR: 1.97, 95% CI: 1.21-3.19). No significant differences were found in allele or genotype distributions of the –2578C > A, -460 T > C, +405G > C and +936C > T polymorphisms between endometriosis cases and controls. A total of six haplotypes were inferred derived from four polymorphisms (-2578C > A, -460 T > C, -1154G > A and +405G > C). There was a protective association between CCGG haplotype and endometriosis, either considering all cases (OR: 0.36, 95% CI: 0.15–0.86), DIE (OR: 0.37 95% CI: 0.15 – 0.90) or stages III-IV (OR: 0.35 95% CI: 0.13 – 0.95).

Conclusions

The present results indicate a positive association between VEGF -1154G > A and the risk of developing endometriosis, whereas the CCGG haplotype may be protective against the development of disease.

Effect of genetic polymorphisms of vascular endothelial growth factor on left ventricular hypertrophy in patients with systemic hypertension

Vascular endothelial growth factor (VEGF) is a cytokine involved in angiogenesis and upregulated during adaptive heart hypertrophy. Downregulation of VEGF seems to trigger the transition from adaptive to dilated cardiac hypertrophy. We investigated for the first time whether 3 clinically relevant polymorphisms in the VEGFA gene are associated with altered echocardiographic parameters in hypertensive patients. We determined genotypes for 3 polymorphisms in VEGFA promoter in 179 hypertensive patients and 169 healthy controls: g.-2578C>A (rs699947), g.-1154G>A (rs1570360), and g.-634G>C (rs2010963). Although the variant genotypes of the g.-634G>C (GC + CC) were associated with reduced left ventricular mass index (p = 0.030), the variant genotypes for the g.-1154G>A (GA + AA) were associated with reduced ejection fraction (p = 0.008). In addition, we found that VEGFA haplotypes were associated with altered ejection fraction (p = 0.024). The AAG haplotype was associated with reduced ejection fraction (p = 0.006), whereas the AGG haplotype was associated with increased ejection fraction (p = 0.010). Our results suggest that VEGF polymorphisms affect cardiac remodeling. Genotypes for VEGFA polymorphisms can be useful to help to identify hypertensive patients at greater intrinsic risk for heart failure.

Polymorphisms and haplotypes in candidate genes related to angiogenesis and endothelial dysfunction in preeclampsia

Valenzuela and colleagues have recently reviewed some polymorphisms in important candidate genes involved in different pathogenic mechanisms related to preeclampsia (PE) and concluded that various studies in different populations have identified maternal polymorphisms associated with PE. However, we would like to contribute to some studies regarding candidate genes related to angiogenesis and endothelial dysfunction in PE performed in the Brazilian population. Specifically, genotypes and haplotypes formed by polymorphisms of VEGF, eNOS and MMP-9, along with an example of the interaction among these genes in the prediction of PE. Our suggestions may provide additional information with clinical relevance to PE susceptibility.

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.

Functional VEGF haplotypes affect the susceptibility to hypertension

We examined whether vascular endothelial growth factor (VEGF) polymorphisms (C-2578A, G-1154A and G-634C) are associated with hypertension, response to antihypertensive therapy and nitric oxide (NO) formation. Substudy 1 compared the distribution of VEGF genotypes and haplotypes in 178 patients with arterial hypertension (100 whites and 78 blacks) and 186 healthy controls (115 whites and 71 blacks). Substudy 2 compared the distribution of VEGF markers in 82 patients with controlled hypertension, 89 patients with resistant hypertension and 101 normotensive (NT) patients. In substudy 3, plasma nitrite/nitrate (NOx) levels were determined (chemiluminescence assay) in 64 NT subjects and 48 hypertensive (HTN) subjects, and the distribution of VEGF markers was compared in subjects having low NOx with subjects having high NOx. Although the substudy 1 showed no differences in genotypes or allele distributions for the three VEGF polymorphisms between NT and HTN subjects, the 'C-A-G' haplotype was more common in white NT subjects than in the white HTN subjects, and the 'C-A-C' haplotype was more frequent in black and white HTN subjects than in black and white NT subjects. The substudy 2 showed similar results, with no differences between responsive and resistant HTN subjects. The substudy 3 showed that the 'C-A-G' haplotype, which had a protective effect against hypertension, was significantly more common in subjects with higher NOx concentrations than in subjects with lower NOx concentrations. VEGF haplotypes are associated with hypertension, and the haplotype associated with normotension was more common in subjects with increased NO formation, possibly offering a mechanistic clue for our findings.

Vascular endothelial growth factor haplotypes associated with childhood obesity

Expansion of adipose tissue in obesity is associated with angiogenesis and adipose tissue mass depends on neovascularization. Vascular endothelial growth factor (VEGF) is the main angiogenic factor in the adipose tissue, and VEGF expression is tightly regulated at both transcriptional and translational levels. However, no previous study has tested the hypothesis that genetic polymorphisms in the VEGF gene could affect susceptibility to obesity. To test this hypothesis, we compared the distribution of genotypes and haplotypes including three VEGF genetic polymorphisms in obese children and adolescents with those found in healthy controls. We studied 172 healthy children and adolescents and 113 obese children and adolescents. Genotypes of three clinically relevant VEGF polymorphisms in the promoter region (C-2578A, G-1154A, and G-634C) of the VEGF gene were determined by TaqMan allele discrimination assay and real-time polymerase chain reaction. VEGF haplotypes were inferred using Haplo.stats and PHASE 2.1 programs. We found no differences in the distributions of VEGF genotypes and alleles (p > 0.05). However, the CAG haplotype was more frequent in the obese group than in the control group (4% versus 0%, respectively, in white subjects; p = 0.008; odds ratio = 10.148 (95% confidence interval: 1.098-93.788). Our findings suggest that VEGF haplotypes affect susceptibility to obesity in children and adolescents.

Papel do fator de crescimento vascular endotelial na angiogênese e na retinopatia diabética

A retinopatia diabética (RD) é uma complicação microvascular do diabetes melito, sendo importante causa de cegueira adquirida. Fatores angiogênicos, como o vascular endothelial growth factor (VEGF), estão envolvidos na patogênese da RD. O VEGF-A é uma citocina potente e multifuncional que atua por meio dos receptores VEGFR-1 e VEGFR-2 expressos no endotélio vascular causando aumento da permeabilidade vascular e estímulo à neovascularização em processos fisiológicos e patológicos. O VEGFR-2 é o principal mediador mitogênico, angiogênico e do aumento da permeabilidade vascular. Alguns polimorfismos do VEGF têm sido estudados na suscetibilidade e risco de progressão da RD. Importante associação entre o polimorfismo 634C/G e a presença de RD é relatada principalmente em relação ao alelo C. A homozigose CC estaria relacionada à RD proliferativa (RDP) e a níveis sérico e vítreo aumentados de VEGF, sugerindo que a presença do alelo C seja um fator de risco independente para RD. Os conhecimentos sobre o VEGF levaram ao desenvolvimento de agentes antiVEGF com o objetivo de inibir a neovascularização patológica e são uma realidade na prática médica do tratamento da RD.

Gene polymorphism of vascular endothelial growth factor -1154 G>A is associated with hypertensive nephropathy in a Hispanic population

The aim of this study was to determine the association between hypertensive nephropathy and gene polymorphisms of vascular endothelial growth factor (VEGF) in a self-reported Hispanic patient group. A total of 155 Hispanic living kidney donors as controls and a total of 86 Hispanic kidney transplant patients, whose renal failure was attributed to hypertensive nephropathy after ruling out diabetes mellitus or other causes, were genotyped for four different single nucleotide polymorphisms of VEGF: -2578 C>A (rs699947), -1154 G>A (rs1570360), -460 C>T (rs833061), and +936 C>T (rs3025039). The homozygous mutant type (AA) of VEGF -1154 G>A (rs1570360) was found with significantly higher frequency in the hypertensive nephropathy patients than in controls. On the other hand, homozygous wild type (GG) was found less frequently in the hypertensive nephropathy patient group than in the control group. Linkage disequilibrium (LD) analyses revealed a high degree of LD among VEGF -2578 C>A (rs699947), VEGF -1154 G>A (rs1570360), and VEGF -460 C>T (rs833061). The haplotype analysis revealed that two haplotypes, CGTC and CATC (in the order of VEGF -2578 C>A (rs699947), -1154 G>A (1570360), -460 C>T (rs833061), and +936 C>T (3025039)), were significantly associated with hypertensive nephropathy in Hispanic patients. Hence, the -1154 G>A polymorphism (rs1570360) and two haplotypes (CGTC and CATC) of VEGF appear to be associated with hypertensive nephropathy in Hispanic patients who developed end-stage renal disease requiring kidney transplant.

Interethnic differences in the distribution of matrix metalloproteinases genetic polymorphisms are consistent with interethnic differences in disease prevalence

Interethnic differences exist in disease prevalence, especially with regard to cancer and cardiovascular diseases, which involve altered expression or activity of matrix metalloproteinases (MMPs). The hypothesis being tested in this study is that interethnic differences exist between blacks and whites with regard to the distribution of genetic variants of MMP polymorphisms and haplotypes. We examined the distribution of polymorphisms of MMP-2 and MMP-9 genes in 177 black and 140 white subjects. We studied the following polymorphisms: the C(-1306)T in the promoter of the MMP-2 gene, the C(-1562)T and a microsatellite -90(CA)(14-24) in the promoter, and the Q279R in exon 6 of the MMP-9 gene. We have also compared our results with those from Hapmap or Seattle SNPs Projects and estimated the haplotype frequency in these two ethnic groups. The "C" allele for the C(-1306)T polymorphism was more common in blacks (91.5%) than in whites (80.4%; p<0.0001). The "T" allele for the C(-1562)T polymorphism was more common in blacks (15.0%) than in whites (8.9%; p=0.0279), as well as the alleles with >21 repeats for the -90(CA)(14-24) were more common in blacks than in whites (61.9% in blacks and 49.3% in whites; p=0.0017). We found no interethnic differences for the Q279R polymorphism. Moreover, two haplotypes that combine "detrimental" alleles were found at higher frequencies in blacks than in whites (31% vs. 16.4%, respectively; p<0.05). The interethnic differences being reported here replicate those previously found with smaller number of subjects in the Hapmap or Seattle SNPs data and may help explain the higher prevalence of cancer and cardiovascular diseases in blacks compared with whites. Our findings suggest a proportional significance of these polymorphisms in each ethnic group.

Vascular endothelial growth factor (VEGF) and endothelial nitric oxide synthase (NOS3) polymorphisms are associated with high relapse risk in childhood acute lymphoblastic leukemia (ALL)

BACKGROUND

Angiogenesis has been shown as an important process in hematological malignancies. It consists in endothelial proliferation, migration, and tube formation following pro-angiogenic factors releasing, specially the vascular endothelial growth factor (VEGF), which angiogenic effect seems to be dependent on nitric oxide (NO). We examined the association among functional polymorphisms in these two angiogenesis related genes: VEGF (-2578C>A, -1154G>A, and -634G>C) and NOS3 (-786T>C, intron 4 b>a, and Glu298Asp) with prognosis of childhood acute lymphoblastic leukemia (ALL).

METHODS

The genotypes were determined and haplotypes estimated in 105 ALL patients that were divided in 2 groups: high risk (HR) and low risk of relapse (LR) patients. In addition, event-free survival curves according to genotypes were assessed.

RESULTS

The group HR compared to the LR showed a higher frequency of the alleles -2578C and -634C and the haplotype CGC for VEGF (0.72 vs. 0.51, p<0.008; 0.47 vs. 0.26, p<0.008; and 42.1 vs. 14.5, p<0.006; respectively) and a lower frequency of the haplotype CbGlu (0.4 vs. 8.8,p<0.006), for NOS3.

CONCLUSION

Polymorphisms of VEGF and NOS3 genes are associated with high risk of relapse, therefore may have a prognostic impact in childhood ALL.