For instance, PER2 mRNA and protein expression was down-regulated in glioma stem cells (GSCs) compared to non-stem glioma cells, while PER2 overexpression induced GSC cell cycle arrest at the G0/G1 phase and suppression of proliferation, a stem cell-like phenotype and invasion capability by targeting the Wnt/β-catenin signaling pathway [173]. Here, PER2 is linked to central nervous system cancer.