Following two seminal publications in 2005 demonstrating greatly increased sensitivity of BRCA1/2 mutant cancer cells to poly(ADP-ribose) polymerase (PARP) inhibition1,2, PARP inhibitors (PARPi) have been extensively tested for their potential as single therapeutic agents based on the concept of tumor-specific synthetic lethality3–5. The gene discussed is PARP1; the disease is neoplasm.