Utilizing a panel of breast tumor cell lines, we observed a remarkable difference in DAC sensitivity, with BRCA1 mutated HRD cell lines (MDA-MB-436 and HCC1937) demonstrating significantly enhanced susceptibility even at a very low drug concentration (15 nM), compared to homologous recombination proficient (HRP) cell lines (Fig. 2B). This evidence concerns the gene BRCA1 and breast neoplasm.