HDAC1 and ovarian cancer: We found that PARP inhibitors Niraparib and Olaparib were unable to significantly promote HRD-EXCUTE signature, but the combination of PARPi and the selective HDAC1/3 inhibitor Entinostat further improved HRD-EXCUTE in ovarian cancer (Fig. 4C-E; Supplementary Fig. S4E-F).