PARP1 and esophageal squamous cell carcinoma: Expression of a siRNA-resistant PARylator (PARylator.siR), but not a PARP1-binding-deficient mutant (PARylator.siR‐ΔE3), partially restored PARP1 chromatin enrichment in PARylator-depleted ESCC cells (Fig. 5g), indicating that PARylator-PARP1 interaction is critical for efficient PARP1 chromatin association.