PARP1 and glioblastoma: Surprisingly, in the same CRISPR-based screens that revealed the critical role of the FA genes in TMZ/MNNG resistance, PARP1 depletion did not hyper-sensitize MGMT-negative glioblastomas to TMZ (MacLeod et al., 2019) and led to only a minor increase in MNNG sensitivity in RPE1 cells (Olivieri et al., 2020).