We and several colleagues showed that a combination of small-molecule inhibitors targeting the poly-ADP ribose polymerase (PARP) could be a highly effective therapy for IDH-mutated malignancies.64,75,76 Owing to the suppression of HR pathways, IDH-mutated cells resemble serious DNA repair defects, which are commonly seen in cancers with BRCA mutations (“BRCAness”). This evidence concerns the gene IDH1 and cancer.