PARP1 and cancer: As PARylation is a highly dynamic and transient process, the inhibition of both PAR glycohydrolase and PARP could reduce the repair efficiency of SSBs, exhibiting their anticancer efficiency.733 Especially, PARP inhibitors have been demonstrated to block the SSB repair pathway and trigger synthetic lethality in cancers with homologous recombination (HR) deficiency which results in impaired DNA double-strand breaks (DSB) repair.734,735