XRCC1 and neoplasm: Among negatively selected genes, 43 DDR genes—including well-characterized tumor suppressors and DDR regulators (e.g., BRCA2, CUL5, MRE11, RNF4, XRCC2, FANCA, XRCC1, SLX4, RAD54B) showed significant reductions in sgRNA abundance following PARPi treatment.