AQP1 and ependymoma: AQP1 overexpression has been observed in diverse types of gliomas, such as glioblastoma, astrocytomas, oligodendrogliomas, ependymomas and glioastrocytomas; the levels of expression have been reported to correlate with the grade of malignancy and invasiveness of the tumors [66,67,68,69,70,71,72].