Vascular endothelial growth factor 936 C/T polymorphism in cancer patients

C936T polymorphism of the VEGF gene in relation to the risk and the clinical and biological characteristics of sporadic colorectal adenocarcinoma

Background

One of the main glycoproteins responsible for angiogenesis is the vascular endothelial growth factor. It is believed that C936T polymorphism, located in the VEGF gene, is correlated with susceptibility towards development of sporadic colorectal adenocarcinoma. The aim of this study was to identify the frequencies of the genotypes of C936T polymorphism of the VEGF gene in patients with sporadic colorectal adenocarcinoma, in comparison with controls, and whether this correlates with the degree of tumor invasion, lymph node involvement and occurrence of metastases at the time of the diagnosis. The analysis was done on 261 patients with sporadic colorectal adenocarcinoma and 261 controls. The genotypes of C936T polymorphism were evaluated by means of the polymerase chain reaction and enzyme digestion, using peripheral blood samples.

Results

The occurrences of genotype 936CC were similar in the two groups (80.5% versus 78.5%, p = 0.2288). In relation to tumor location, lymph node involvement, infiltration and tumor metastasis, no statistically significant results were obtained (p = 0.3116, p = 0.8485, p = 0.9408 and p = 0.2861, respectively).

Conclusion

C936T polymorphism of the VEGF gene did not influence the occurrence of sporadic colorectal adenocarcinoma development and did not correlated with the degree of tumor invasion, lymph node involvement and occurrence of metastases.

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.

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.

VEGFA +936C>T polymorphism and cancer risk: a meta-analysis

Vascular endothelial growth factor A (VEGF-A), a major driver of physiological and pathological angiogenesis, plays important roles in the etiology and metastasis of cancers. The +936C>T polymorphism in the 3'-untranslated region of the VEGFA gene has been implicated in cancer risk and is related to VEGF-A protein production; however, published data have been conflicting. To derive a more precise estimation of the relationship, a meta-analysis was performed of 13,293 cancer cases and 12,308 control subjects from 29 published case-control studies. Odds ratios (ORs) with 95% confidence intervals (CIs) were estimated to assess the association between +936C>T polymorphism and cancer risk. The meta-analysis indicated that individuals with the +936 T had increased risk of oral cancer (OR = 1.39, 95% CI = 1.03-1.88), although no association was found in the contrast of T versus C (OR = 1.00, 95% CI = 0.91-1.10) in the pooled analyses. This meta-analysis supports the idea that VEGFA + 936 T is associated with increased risk of oral cancer. To draw comprehensive and true conclusions, further prospective studies with larger numbers of participants worldwide are needed to examine associations between VEGFA + 936C>T polymorphism and cancer risk.

Polymorphisms in VEGF and IL-8 predict tumor recurrence in stage III colon cancer

BACKGROUND

Identifying molecular markers for tumor recurrence is critical in successfully selecting patients with stage III colon cancer who are more likely to benefit from adjuvant chemotherapy. The present study analyzed a subset of 10 polymorphisms within eight genes involved in the tumor angiogenesis pathway and their impact on prognosis in stage III colon cancer patients treated with adjuvant chemotherapy.

PATIENTS AND METHODS

Blood samples were obtained from 125 patients with locally advanced colon cancer at University of Southern California medical facilities. DNA was extracted from peripheral blood and the genotypes were analyzed using PCR-restriction fragment length polymorphism and 5'-end [gamma-(33)P] ATP-labeled PCR protocols.

RESULTS

Polymorphisms in vascular endothelial growth factor (VEGF) (C+936T; P = 0.003, log-rank test) and interleukin-8 (IL-8) (T-251A; P = 0.04, log-rank test) were independently associated with risk of recurrence in stage III colon cancer patients. In combined analysis, grouping alleles into favorable versus nonfavorable alleles, high expression variants of VEGF C+936T and IL-8 T-251A were associated with a higher likelihood of developing tumor recurrence (P < 0.001).

CONCLUSION

High expression variants of VEGF C+936T and IL-8 T-251A were associated with shorter time to tumor recurrence, indicating that the analysis of angiogenesis-related gene polymorphisms may help to identify patient subgroups at high risk for tumor recurrence.