ESR1 and metastatic neoplasm: The positively correlated CTCF signature (i.e., using genes that were repressed after CTCF knockdown) was significantly enriched in both MCF7 ESR1 mutant cells (Fig. 4a) and metastatic tumors (Fig. 4b) compared to their WT counterparts, whereas E2 stimulation had no effect (Fig. 4a).