H2AX and neuroblastoma: Corroborating potentiated apoptosis induction, concomitant KO of VRK1 and VRK2 increased DNA damage foci (phospho-histone H2AX) in VRK2hi GBM cells (Figure 5B) and in 2 NB cell lines after degradation of dTAG-VRK1 (Figure 5C).