It has been reported that KDM4B/JMJD2B are highly expressed in estrogen receptor (ER)-positive breast cancer, in which KDM4B can bind to the ER, then demethylate repressive histone mark H3K9me3 and recruit members of the SWI/SNF-B and MLL2 chromatin-remodeling complexes to induce gene expression in an estrogen-dependent manner. Here, KDM4B is linked to breast cancer.