VEGF T-1498C polymorphism, a predictive marker of differentiation of colorectal adenocarcinomas in Japanese

The association of VEGF rs833061 and rs2010963 polymorphisms with susceptibility to colorectal cancer in an Iranian population

Vascular endothelial growth factor (VEGF) is one of the most important regulators of angiogenesis. Several single nucleotide polymorphisms (SNPs) are associated with the VEGF overexpression and tumor progression in several cancers. This study aimed to determine the association of VEGF rs833061 and rs2010963 polymorphism and their haplotypes with susceptibility to colorectal cancer (CRC) in the Iranian population. A total of 284 colorectal cancer patients (37.3% women, 62.7% men) were enrolled in this study. Healthy controls without evidence of cancer history or family cancer predispositions were frequency-matched to the cases by sex and age (± 5 years). Genotyping was performed by the Sequenom mass ARRAY method and the genotype distribution and risk estimate were analyzed by SPSS software. The correlation between the genotypes and clinicopathological parameters (Dukes stage, phenotype, location, differentiation, and tumor size) among colorectal cancer patients were investigated. We found a significant relationship, between rs833061T/C genotype and their TG haplotype with the age of diagnosis < 60; (p = 0.012, p = 0.014) and rs2010963G/C genotype with female gender and TG haplotype with third and fourth tumor stage and tumor location (p = 0.04and p = 0.047). This study showed that rs833061T/C genotype and TG haplotype increase the susceptibility to colon cancer in the Iranian population. This susceptibility has a significant relationship with the age of diagnosis and different stages of the tumor.

Prognostic significance of vascular endothelial growth factor polymorphisms in colorectal cancer patients

AIM

To investigate the associations of the genetic polymorphisms of vascular endothelial growth factor A (VEGF-A) -1498C>T and -634G>C, with the survival of patients with colorectal cancer (CRC).

METHODS

A prospective cohort consisting of 131 Brazilians patients consecutively operated on with a curative intention as a result of sporadic colorectal carcinoma was studied. DNA was extracted from peripheral blood and its amplification and allelic discrimination for each genetic polymorphism was performed using the technique of polymerase chain reaction (PCR) in real-time. The real-time PCR technique was used to identify the VEGF-A -1498C>T (rs833031) and -634G>C (rs2010963) polymorphisms. Genotyping was validated for VEGF-A -1498C>T polymorphism in 129 patients and for VEGF-A -634G>C polymorphism in 118 patients. The analysis of association between categorical variables was performed using logistic regression, survival by Kaplan-Meier method and multivariate analysis by the Cox regression method.

RESULTS

In the univariate analysis there was a significant association (OR = 0.32; P = 0.048) between genotype CC of the VEGF-A -1498C>T polymorphism and the presence of CRC liver metastasis. There was no association between VEGF-A -1498C>T polymorphism and VEGF-A -634G>C polymorphism with further clinical or anatomopathologic variables. The genotype CC of the VEGF-A -1498C>T polymorphism was significantly correlated with the 5-year survival (P = 0.032), but not significant difference (P = 0.27) was obtained with the VEGF-A -634G>C polymorphism with the 5-year survival in the univariate analysis. The genotype CT (HR = 2.79) and CC (HR = 4.67) of the polymorphism VEGF-A -1498C>T and the genotype CC (HR = 3.76) of the polymorphism VEGF-A -634C>G acted as an independent prognostic factor for the risk of death in CRC patients.

CONCLUSION

The CT and CC genotypes of the VEGF-A -1498C>T and the CC genotype of the VEGF-A -634C>G polymorphisms are prognostic factors of survival in Brazilians patients with sporadic colorectal carcinoma.

Association of a vascular endothelial growth factor polymorphism with the development of bronchopulmonary dysplasia in Japanese premature newborns

Our objective was to correlate vascular endothelial growth factor (VEGF) genetic polymorphisms with the risk of bronchopulmonary dysplasia (BPD) development in premature newborns. Fifty-five newborns with BPD (BPD: median gestational age [GA]: 27 weeks, birthweight [BW]: 786 g) and 42 newborns without BPD (non-BPD: median GA: 29 weeks, BW: 1,165 g), who were born at <32 weeks gestational age and were admitted to Kobe University Hospital, were included. BPD was defined as oxygen dependency at 36 weeks postmenstrual age. Genomic DNA was extracted from the umbilical cord, cord blood, or buccal mucosa. Six VEGF genotypes (-1498T > C, -1154G > A, -634C > G, -7C > T, 936C > T, and 1612G > A) were determined by DNA sequencing. Clinical characteristics, and allele and genotype frequencies of VEGF in the BPD and non-BPD groups were analyzed. G allele frequencies in -634C > G of the BPD group were significantly higher than in the non-BPD group (66.4% vs. 50%, P = 0.02). -634C > G genotype distributions differed significantly between the BPD and non-BPD groups (BPD: CC 7%/CG 53%/GG 40%; non-BPD: CC 24%/CG 52%/GG 24%; P = 0.04). Multivariate logistic regression showed that duration of ventilation, VEGF-634G > C G alleles, and male gender were independent risk factors for BPD. In conclusion, polymorphism VEGF -634C > G may influence the risk of BPD.

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.

Vascular endothelial growth factor polymorphisms and clinical outcome in colorectal cancer patients treated with irinotecan-based chemotherapy and bevacizumab

The aim of the study was to evaluate the association of vascular endothelial growth factor (VEGF) genotypes with treatment efficacy in a randomized trial. This study compared two chemotherapy regimens (FOLFIRI versus XELIRI) combined with bevacizumab, as first-line treatment for metastatic colorectal cancer. DNA was extracted from blood samples of 173 patients participating in the trial. Genotyping was performed for selected SNPs (VEGF-1154, +936, -634, -2578 and -1498). All candidate genotypes were evaluated for associations with overall survival (OS), progression-free survival (PFS) and response rate (RR). There were no significant differences with respect to the distribution of genotypes in the treatment groups. The VEGF-1154 GG genotype was more frequent in patients not responding to treatment compared with responders (65.5 versus 39.8%, P = 0.032). Furthermore, the VEGF-1154 GG genotype was associated with inferior median OS compared with GA (hazards ratio = 1.68; 95% confidence interval: 1.10-2.57; P = 0.016) or with the alternative genotypes (GA and AA) combined (hazards ratio = 1.62; 95% confidence interval: 1.09-2.40; P = 0.017). In multivariate analysis, the VEGF-1154 GG genotype remained a significant adverse factor for OS. Our results support the potential predictive ability of VEGF genotypes in patients with metastatic colorectal cancer receiving irinotecan-based chemotherapy plus bevacizumab, in terms of RR and OS. However, current results should be validated prospectively, in larger cohorts.

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.

Gastric cancer risk predisposition and prognostic significance of vascular endothelial growth factor (VEGF) gene polymorphisms--a case-control study in an Omani population

Vascular endothelial growth factor (VEGF) plays a central role in angiogenesis, tumor growth, and metastasis. We investigated the associations between VEGF gene polymorphisms and gastric cancer (GC) risk predisposition and prognostic characteristics in an Omani population, an ethnic group which has not been studied previously. We analyzed three VEGF polymorphisms (+405 G/C, -460 T/C, and +936 C/T) by the extraction of genomic DNA from peripheral blood of 130 GC patients and 130 control subjects followed by VEGF genotyping using polymerase chain reaction restriction fragment length polymorphism (PCR-RFLP) analysis. There were no significant associations between the VEGF polymorphisms and GC risk. There were significant correlations between the +405 C/C genotype and both poor tumor differentiation (P = 0.007) and lymph node metastasis (P = 0.03) and between the -460 T/T genotype and poor tumor differentiation (P = 0.03) with a statistical trend toward lymph node involvement (P = 0.05). VEGF gene polymorphisms had no significant effects on survival, but the VEGF +405 G/G genotype had a statistical trend toward lower survival rate with a hazard ratio of 1.6 [95% CI, 0.9-2.9] compared with the VEGF +405 CC/GC combined genotype (P = 0.049). Multivariate analysis showed that disease stage at diagnosis and the +405 G/G genotype were independent variables of adverse prognostic significance. There were no associations between the six common haplotypes identified and both GC risk predisposition and survival. The current study suggests that VEGF polymorphisms have no role in GC risk predisposition, but may have prognostic significance in GC patients.

The role of vascular endothelial growth factor SNPs as predictive and prognostic markers for major solid tumors

Angiogenesis is crucial for development and metastasis of tumors, and vascular endothelial growth factor (VEGF) is a key mediator of this process. The importance of VEGF in tumorigenesis and tumor progression makes it an attractive target for the development of anticancer therapies. Inhibition of angiogenesis has shown promising clinical efficacy; however, not all patients treated with antiangiogenic agents derive benefit from them. Some patients are predisposed to refractory disease, whereas others develop resistance after initial response. Patients may also have different severity of drug-related adverse events. Optimization of drug administration based on disease status and individual responsiveness is important in limiting the treatment failure and minimization of side-effects. Single nucleotide polymorphisms (SNP) in VEGF may alter VEGF protein concentrations, influence the process of angiogenesis, and may relate to interindividual variation in the risk and progression of selected tumors, and their resistance to treatments. This review examines the role of SNPs in the VEGF gene as predictive and prognostic markers for major solid tumors, including the breast, non-small cell lung, colorectal, and prostate cancers. Selected VEGF SNPs seem to be associated with risk of these cancers; however, there is lack of unanimity in findings, in part influenced by differences in study design and analysis.

Pharmacogenetics in chemotherapy of colorectal cancer

Although in recent years, chemotherapeutic options for colorectal carcinoma have expanded, overall response rates are still too low, with high rates of toxicity. Pharmacogenetics aim at predicting both treatment response and adverse effects in individual patients. This review describes the current knowledge of pharmacogenetic markers in the systemic treatment of colorectal cancer. UGT1A1*28 leads to reduced conjugation of SN-38, the active metabolite of irinotecan, resulting in an increased rate of adverse effects, especially neutropenia. To a lesser extent, increased 5-FU toxicity is predicted by DPYD*2A. A variable number of tandem repeats polymorphism in the thymidylate synthase enhancer region, in combination with a single nucleotide polymorphism C>G, may predict poorer response to 5-FU. Efficacy of oxaliplatin is influenced by polymorphisms in components of DNA repair systems, such as ERCC1 and XRCC1. Polymorphic changes in the endothelial growth factor receptor probably predict cetuximab efficacy. Furthermore, the antibody-depended cell-mediated cytotoxic effect of cetuximab may be reduced by polymorphisms in the immunoglobin G fragment C receptors. Bevacizumab efficacy is suspected to be influenced by polymorphisms in the VEGF gene and the hypoxia inducible factor 1alpha gene. Although the interpretation of pharmacogenetic studies is complicated, results imply a promising way of pretreatment prediction of chemotherapy efficacy and toxicity.