HIF1A and astrocytoma (excluding glioblastoma): Consistent with the findings of Shen et al. [16], silencing of the HIF-1α gene significantly inhibited the proliferation, invasion, and metastatic ability of U87 cells; in malignant astrocytomas, HIF-1α was mainly present in cells arranged in a pseudo-fenestrated pattern near the necrotic zone and in cells infiltrating normal tissue around the tumor [17].