PARP1 and breast adenocarcinoma: To ensure the broad applicability of PARP inhibitors (PARPi) against XRN2 vulnerabilities, here, we evaluated the effects that other FDA-approved PARPi, Rucaparib, and Olaparib have in XRN2-depleted A549 (lung carcinoma) and MDA-MB-231 (mammary adenocarcinoma) cells (Figure 1).