Prognostic value of vascular endothelial growth factor and its receptors Flt-1 and Flk-1 in astrocytic tumours

Background. Vascular endothelial growth factor (VEGF)/vascular permeability factor (VPF) is an important regulator of angiogenesis and vascular permeability. Method. We examined immunohistochemically expressions of VEGF and its corresponding receptors Flt-1 and Flk-1 in a series of 50 astrocytic tumours, and correlated their expressions with the degree of angiogenesis, brain edema and prognosis. Findings. There were significant relationships between VEGF, Flk-1 expressions and glioma malignancy grading, intratumoural vascularity and peritumoural brain edema, respectively. Patients with VEGF positive low grade astrocytoma and glioblastoma multiforme had a significantly shorter mean overall survival time than those with negative tumours (P = 0.0010 and 0.0180, respectively). Flk-1 is also a significant prognostic factor within each tumour grade, which has a negative impact on overall survival. Additionally, overexpression of VEGF and Flk-1 were significantly associated with earlier recurrence in patients with low grade astrocytomas (P = 0.0018 and 0.0240, respectively). Interpretation. It is possible to subcategorize each grade of astrocytic tumours based on their VEGF and Flk-1 staining pattern, which may be crucial in predicting the biological behavior of tumours and thus provide useful information with regard to adequate treatment.