ESR1 and breast cancer: In breast cancer we have shown that HIF-1α and ERα can coordinate expression of genes, such as KDM4B, whose expression is driven by both ERα and HIF-1α and epigenetically regulates the G2/M phase of cell cycle progression in breast cancer cells [63] and other cancer cell lines (unpublished data), as the expression of several key cell cycle genes is correlated with changes in the KDM4B substrate, H3K9me3 [63,104].