BRD9 and leukemia: Then, using cellular competition assays, we confirmed that double knockout of either Brd9&Jmjd6 or Kat6a&Jmjd6 had a synergistic suppressive effect on RN2 proliferation, but had minimal-to-no effect on both NIH3T3c12 fibroblast and B16-F10c12 cellular proliferation, suggesting that these two screen-identified synthetic sick/lethal genetic interactions might be leukemia-specific (Fig. 3c and Supplementary Figs. 16 and 17).