PTEN and central nervous system cancer: In PTEN-deficient glioma cells, the activated AKT pathway inactivates GSK-3β by promoting Ser9 phosphorylation, thereby reducing GSK-3β-mediated degradation of IRF1, leading to the up-regulation of the transcription factor IRF1, which enters the nucleus to promote LGALS-9 gene transcription and Gal-9 expression.