Evaluation of mast cells and hypoxia inducible factor-1 expression in meningiomas of various grades in correlation with peritumoral brain edema.

Meningiomas are common primary brain tumors. However, they are often complicated by significant peritumoral brain edema, which leads to surgery difficulties and prolonged hospitalization. The aim of this study was to evaluate the presence of mast cells and expression of hypoxia inducible factor-1 (HIF-1) in correlation with the grade of meningioma and presence of peritumoral brain edema. Immunohistochemistry was performed with specific antibodies against tryptase (mast cells) and HIF-1 in low grade meningiomas (estimated as G1) and high grade meningiomas (estimated as G2 or G3). Peritumoral brain edema observed in MRI was graded using Steinhoff classification. Tryptase expression was observed in 40.4 % low grade meningiomas and in 90 % high grade cases; HIF-1 in 55.7 % low grade and in 84 % high grade meningiomas. There was a statistically significant correlation between HIF-1 and tryptase expression in both groups (p = 0.003). Presence of peritumoral brain edema statistically correlated with tryptase (p = 0.001) and HIF-1 expression (p = 0.004). Mast cells as well as hypoxia are involved in meningioma progression, and may be associated with the formation of peritumoral brain edema leading to surgery complication and recovery. Therefore, they may be useful markers in predicting the clinical course of meningioma cases.