CDK1 and glioblastoma: The majority of tumors with low pSer9GSK3β labeling showed low levels of both pTyr15- and pThr161-CDC2 levels, whereas the majority of oligodendroglioma and the GBM cores with high pSer9GSK3β also had high levels of both pTyr15- and pThr161-CDC2 levels (Figure 6(g)).