However, increased expression of AQP4 in edematous vs non-edematous meningiomas as well as in meningiomas with larger edema (EI ≥ 2), was detected, confirming previous findings (Gawlitza et al. 2017; Ng et al. 2009; Wang et al. 2011). This evidence concerns the gene AQP4 and meningioma.