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

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.

No associations of a set of SNPs in the Vascular Endothelial Growth Factor (VEGF) and Matrix Metalloproteinase (MMP) genes with survival of colorectal cancer patients

In this study, we aimed to investigate the associations of genetic variations within select genes functioning in angiogenesis, lymph‐angiogenesis, and metastasis pathways and the risk of outcome in colorectal cancer patients. We followed a two‐stage analysis: First, 381 polymorphisms from 30 genes (eight Vascular Endothelial Growth Factor (VEGF) and 22 Matrix Metalloproteinase [MMP] genes) were investigated in the discovery cohort (n = 505). Then, 16 polymorphisms with the lowest P‐value in this analysis were investigated in a separate replication cohort (n = 247). Genotypes were obtained using the Illumina^® HumanOmni‐1‐Quad (discovery cohort) and Sequenom MassArray^® (replication cohort) platforms. The primary outcome measure was overall survival (OS). Kaplan–Meier, univariate and multivariable Cox regression methods were used to test the associations between genotypes and OS. Four SNPs (rs12365082, rs11225389, rs11225388, and rs2846707) had the univariate analysis P < 0.05 in both the discovery and replication cohorts. These SNPs are in linkage disequilibrium with each other to varying extent and are located in the MMP8 and MMP27 genes. In the multivariable analysis adjusting for age, stage, and microsatellite instability status, three of these SNPs (rs12365082, rs11225389, rs11225388) were independent predictors of OS (P < 0.05) in the discovery cohort. However, the same analysis in the replication cohort did not yield statistically significant results. Overall, while the genetic variations in the VEGF and MMP genes are attractive candidates as prognostic markers, our study showed no evidence of associations of a large set of SNPs in these genes and overall survival of colorectal cancer patients in our study.

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.

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

BACKGROUND

Angiogenesis plays an important role in tumor development, progression, and metastasis. Vascular endothelial growth factor (VEGF) is a key regulator of angiogenesis. However, the contribution of common VEGF polymorphisms to colorectal cancer (CRC) prognosis remains unclear.

METHODS

We have genotyped four polymorphisms of VEGF (-2578C>A, -1154G>A, -634G>C, and 936C>T) in 350 CRC cases from the Korean population. The genotyping of VEGF polymorphisms was performed by polymerase chain reaction-restriction fragment length polymorphism assay.

RESULTS

Although not every VEGF polymorphism was significantly correlated with patient prognosis in overall 350 CRC patients, we found that the VEGF -2578CA genotype was associated with a significantly poor prognosis for rectal cancers compared to the CC genotype (HR = 2.156; 95 % CI 1.090-4.267; P = 0.028). In addition, we found that the -2578A/-1154G/-634G/+936C haplotype was significantly associated with a decreased overall survival (OS) rate in all 350 CRC patients (HR = 2.530; 95 % CI 1.340-4.780; P = 0.004). In combination analysis, we found that the combined VEGF -2578CA+AA/-1154GG genotype was associated with a poor OS rate in all 350 CRC patients (HR = 2.068; 95 % CI 1.159-3.693; P = 0.015).

CONCLUSIONS

The VEGF gene polymorphisms investigated in this study were not found to be independent prognostic markers in Korean CRC populations. However, our results suggest that the VEGF -2578C>A variant may be a potential genetic marker for rectal cancer prognosis. Further large population studies are warranted to define whether the -2578C>A polymorphism is a prognostic marker of rectal cancer.

The predictive value of single nucleotide polymorphisms in the VEGF system to the efficacy of first-line treatment with bevacizumab plus chemotherapy in patients with metastatic colorectal cancer: results from the Nordic ACT trial

PURPOSE

Bevacizumab and chemotherapy is a common choice for first-line treatment of metastatic colorectal cancer (mCRC). So far, no predictive markers have been identified. The aim was to investigate the possible predictive value of single nucleotide polymorphisms (SNPs) in the vascular endothelial growth factor (VEGF) system in this setting.

METHODS

Pre-treatment blood samples and response evaluations were available from 218 of the 249 included patients. All patients received bevacizumab and chemotherapy comprising fluorouracil and leucovorin or capecitabine combined with either oxaliplatin (FOLFOX or XELOX, n = 183) or irinotecan (FOLFIRI or XELIRI, n = 66). Germline DNA was isolated from whole blood, and five SNPs in the VEGF-A gene, one SNP in the VEGF receptor 1 (VEGFR-1) gene and three SNPs in the VEGFR-2 gene were analysed by polymerase chain reaction. Response was evaluated according to RECIST version 1.0, and the association to genotypes was analysed using Fisher's exact test.

RESULTS

The VEGFR-1 319 C/A SNP was significantly associated with response. Objective response was observed in 36% of the patients with CC genotype, 40% with CA and 56% with AA, p = 0.048. The response rates also differed significantly between patients with C-allele containing genotypes (CC + CA) (39%) and patients homozygous for the A-allele (AA) (56%), p = 0.015. There was no correlation between response rates and the remaining SNPs.

CONCLUSIONS

The VEGFR-1 319 C/A SNP is a potential predictive marker for bevacizumab plus chemotherapy in patients with mCRC. Patients with the A allele appeared to have increased response rates. The results call for validation.

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.