Tumor cells that were are refractory to PARPi (abbreviated as “PARPi-Res” in the figure) from both PARPi-treated Brca1-def and Bard1-def tumors were then isolated, re-injected into the mammary glands of new B6/129F1 recipient mice (Fig. 1C,F) and treated as described above. The gene discussed is BRCA1; the disease is neoplasm.