PARP1 and cancer: PARP inhibitors (PARPis) have already been approved for clinical treatment of cancers with homologous recombination (HR) deficiency, while targeting dePARylation is an encouraging alternative strategy to overcome PARPi resistance (Gravells et al., 2017; Chen and Yu, 2019; Pillay et al., 2021; Slade, 2020; Min and Wang, 2009).