Density of microvessels positive for CD105 (endoglin) is related to prognosis in meningiomas

Microvessel density (MVD) is considered to be a prognostic marker in many tumours. Nevertheless, conflicting results were achieved regarding its prognostic role in meningiomas when it was quantified through pan-endothelial markers such as CD34, CD31 or Factor VIII. In the present study, MVD was assessed in meningiomas through the specific marker for neo-angiogenesis CD105. Fifty-four formalin fixed, paraffin embedded, surgical cases of meningiomas (WHO 28 grade I and 26 grade II) as well as ten normal leptomeningeal samples were submitted to immunohistochemical analysis for CD105. CD34 immuno-expression was also evaluated on consecutive parallel sections. For each case, MVD was estimated in terms of number of vessels/mm². CD105 was not evidenced in normal samples, whereas it was demonstrated in the vessels within 14/28 WHO grade I cases and within 24/26 WHO grade II meningiomas. On the contrary, CD34 antibody stained blood vessels in both normal and neoplastic samples; moreover, in each case, it stained more microvessels than CD105 antibody (25.33 ± 21.16 vs. 50.72 ± 26.75). Higher CD105 counts were significantly correlated with higher histological grade and Ki-67 LI > 4%. No statistical significant correlations were encountered between MVD measured by either CD105 and CD34 and sex, age, site of tumour or extent of surgical resection. CD105-MVD, but not CD34-MVD, showed an inverse significant correlation with overall survival and recurrence-free survival. In conclusion, our study suggests the higher specificity of CD105 in comparison to pan-endothelial markers in the evaluation of meningioma neo-angiogenesis, and its higher prognostic significance. CD105 might serve as a target for therapeutic approaches blocking blood supply in meningiomas.