In this work, we have generated and utilized the novel patient-derived BARD1-mutated Ewing sarcoma cell line PSaRC318 as a model to ask the question: can pathogenic variants in the DNA damage repair gene BARD1 enhance sensitivity to PARPi/DNA damage beyond the vulnerability already imparted by the presence of EWS-FLI1? The gene discussed is EWSR1; the disease is Ewing sarcoma.