Based on the effect observed in IDH-mutant glioma and leukemia, in which the IDH mutation caused vulnerability to PARP inhibition, talazoparib, a PARP inhibitor currently approved to treat patients with germline BRCA-mutated (gBRCA) HER2-negative metastatic breast cancer, was tested in chondrosarcoma using conventionally 2D-cultured endogenous IDH-mutant and IDH-wildtype cell lines [27, 39]. The gene discussed is IDH1; the disease is leukemia.