Correlative evidence that tumor cell-derived caveolin-1 mediates angiogenesis in meningiomas

Since it has recently been reported that caveolin-1 (cav-1) may favor the progression of prostatic and renal cancers by stimulating tumor neoangiogenesis, we thought it of interest to analyze the correlation between cav-1 expression and tumor microvessel density (MVD) in meningiomas. In the present study we quantified cav-1 expression by immunohistochemistry and used CD105 immunohistochemical staining to measure MVD. Sixty-two formalin-fixed, paraffin-embedded, surgically resected meningiomas were submitted to the analysis. On the basis of cav-1 immuno-expression, cases were subdivided into meningiomas displaying a low (n = 34) and a high (n = 28) cav-1 immuno-expression, respectively. Mann-Whitney test showed that a significantly higher MVD was present in the cases with a high cav-1 expression than in those with a low expression (mean 24.44 vs. 41.28 microvessels/mm(2)) (P = 0.0001). Moreover, Spearman test revealed a significant positive correlation between cav-1 rate of expression and MVD counts in the meningiomas of our series (r = 0.390; P = 0.0023). Therefore, our study demonstrates the existence of an association between cav-1 expression and neoangiogenesis in meningiomas, suggesting that cav-1 may mediate the progression of these tumors by stimulating the angiogenic process. Besides, it is known that the progression of meningiomas is paralleled by an increase in MVD. The clarification of cav-1 role in the neoangiogensis of meningiomas may open new insights about the possibility of novel therapeutic strategies in these neoplasias.