CRY2 and central nervous system cancer: The levels of cry 2 mRNA were higher in the irradiated glioma group than in the control glioma group at ZT8 (t = –5.135, p< 0.001) and ZT4(t = –4.464, p < 0.001), which represent high and low cry2 expression time points for glioma brain tissues, respectively (Figure 3).