Mutations in BRCA1 or BRCA2 tumor suppressor genes increase the risk of breast and ovarian cancer. In clinical practice, these cancer patients often receive targeted poly ADP ribose polymerase (PARP) inhibitors treatment. According to a recent study published in the journal Science, Stephen C. West from the Francis Crick Institute in the UK showed that inhibition of DNPH1, a protein that eliminates the cytotoxic nucleotide 5-hydroxymethyl-deoxyuridine (hmdU) monophosphate, enhances the…