We found that SETDB2 knockdown significantly increased the percentage of abnormal nuclei in SUM159PT breast cancer cells (Fig. S1A and Fig. 1B), abnormal spindle and chromosome segregation in metaphase and anaphase of mitosis (Fig. S1B and Fig. 1C), and G2/M arrested cells in SUM159PT breast cancer cells (Fig. S1C and Fig. 1D). The gene discussed is SETDB2; the disease is breast cancer.