Angiogenesis and Ewing sarcoma—relationship to pulmonary metastasis and survival

Intratumoral angiogenesis quantified by microvessel density (MVD) has been shown to be a strong prognostic indicator in a number of malignant tumors. Its association with prognosis in Ewing sarcoma has not been previously studied. The aim of our study was to investigate the relationship between angiogenesis and clinical outcome in Ewing sarcoma. Twenty-seven patients with Ewing sarcoma were included in a retrospective immunohistochemical study. Sections from diagnostic biopsies were immunostained using anti–von Willebrand factor antibody and microvessels were counted at 400× magnification on three microscopic fields per patient. Microvessel density was correlated with overall and disease-free survival as a continuous variable using univariate regression analysis and as a dichotomous variable by Kaplan-Meier and log-rank analysis. Correlation between clinicopathologic variables and the degree of angiogenesis was tested using χ 2 test. Increasing MVD was not confirmed to be a poor prognostic factor in univariate analysis. Also, statistically significant difference was not found in overall survival or disease-free survival between patients with high (>31.6 vessels per field) and low (≤31.6 vessels per field) microvessel counts. Finally, there was no difference regarding the metastatic rate between patients with high and low microvessel counts. Our results did not confirm increasing angiogenesis quantified by MVD to be predictive of prognosis or pulmonary metastasis in Ewing sarcoma. The diffuse pattern of distribution of microvessels found in Ewing sarcoma may be responsible for the observed lack of prognostic significance of angiogenesis. Future work is required to assess the prognostic importance of MVD in this disease.