MGMT and glioblastoma: As tumor recurrence progressed and using GAPDH as a reference, the stemness of the tumor decreased, some cellular subpopulations persisted as mesenchymal GBM, followed by differentiation into astrocyte and classic types GBM, subsequently differentiating into neuronal type GBM, and MGMT, SP1, and H3K9ac levels trended upwards in this process (Figure S4L,M and Figure 7M,N).