Similar results were observed for the BRCA1‐mutated cancer cell line SUM149PT (Elstrodt et al, 2006), in which otherwise sublethal concentrations of olaparib (≤ 10 nM) were selectively toxic in BRCA1‐deficient cells in the presence of 0.5 μM CldU (Fig 7C and D). The gene discussed is BRCA1; the disease is cancer.