Accordingly, this review first aims to summarize current research in recurrent glioblastoma such as the molecular pathways and genetic mutations that drive cell proliferation (TERT, PTEN, PI3K/Akt, MSH6, and LTBP4) and paracrine signaling of glioma stem cells (GSCs) [19,20]. The gene discussed is PTEN; the disease is glioblastoma.