26020 Vascular Endothelial Growth Factor, Plasma (VEGF)

​​VEGF-Alpha, VEGF-A, Cytokine

Evaluation of patients with suspected POEMS (polyneuropathy, organomegaly, endocrinopathy, monoclonal gammopathy, and skin changes) syndrome, particularly in differentiating from other forms of polyneuropathy and/ or monoclonal plasma cell disorders.  ​

Elevated circulating concentrations of vascular endothelial growth factor (VEGF) may be observed in a variety of disease states, especially those associated with angiogenesis. Elevated concentrations of VEGF must be interpreted within the clinical context of the patient.​

Normal concentrations of VEGF do not exclude the diagnosis of POEMS (polyneuropathy, organomegaly, endocrinopathy, monoclonal gammopathy, and skin changes) syndrome.

VEGF has limited stability. Following centrifugation, plasma must be either immediately frozen or refrigerated. Samples can only be stored at refrigerated temperatures for 24 hours, after which time samples must be frozen. Storage of plasma for any length of time at room temperature is not acceptable.

The presence of bevacizumab in patient serum interferes with detection of VEGF. Caution should be taken while interpreting results of patients receiving bevacizumab therapy.

​Vascular endothelial growth factor (VEGF) is a critical modulator of angiogenesis (the growth of new blood vessels). In mammals, there are 5 members of the VEGF family, each arising from different genes, with VEGF-A being the most well-studied. VEGF-A promotes angiogenesis by inducing migration of endothelial cells, promoting mitosis of endothelial cells, and upregulating matrix metalloproteinase activity. VEGF-A is regulated by hypoxia, with increased expression when cells detect an environment low in oxygen. Physiologically, VEGF induces new blood vessel formation during embryonic development, after tissue injury, and in response to blocked vessels.

VEGF also regulates pathological vessel formation, such as in tumor growth and metastases. Angiogenesis during tumor development is complex, although it is clear that VEGF plays a key role. ​VEGF also regulates angiogenesis in other disease states including rheumatoid arthritis, osteoarthritis, diabetes, and age-related macular degeneration. In addition, circulating concentrations of VEGF are elevated in patients with polyneuropathy, organomegaly, endocrinopathy, monoclonal gammopathy, and skin changes (POEMS) syndrome, a monoclonal plasma cell disorder. Although the pathologic role of VEGF in POEMS is unclear, it is a useful as a diagnostic marker and for assessing response to therapy. 

In addition to the various genes in the VEGF family, VEGFA has multiple splicing variants. VEGFA 165 is the predominant isoform.​ An internal study has demonstrated that the VEGF assay used by Mayo Clinic Laboratories is specific for the splice variant of VEGF-A 165 and does not detect other isoforms of VEGFA or other VEGF gene products.