Figure 4
VEGF expression correlated with the histology grades of NB tumors and predicted a favorable clinical outcome of NB patients. (A) Immunohistochemical analysis of VEGF expression in tumor tissues of NB patients. Tumors were classified into four categories based on the intensity of VEGF immunostaining: negative, weak, moderate, and strong signals of VEGF. Upper panels shows low magnification images (200× , scale bar, 5 µm) and lower panels indicates the boxed images with high magnification (400× , scale bar, 2 µm). UNB, undifferentiated neuroblastoma. DNB, differentiated neuroblastoma. (B) The correlation between VEGF expression level and the differentiation histology of NB tumor was analyzed in 69 human NB tumor samples. Summation of weak, moderate and strong VEGF immunostaining was recorded as “positive”, thereby 23.5% and 54.3% positive VEGF expression were found in UNB and DNB, respectively. (C) Kaplan-Meier survival analysis according to the expression of VEGF determined by immunohistochemistry in a cohort of 69 NB patients. NB patients with positive VEGF expression in tumor tissues had a significantly higher 5-year predictive survival rate compared to those patients with negative VEGF expression.
