JMJD2A belongs to the cancer-associated gene family of JMJD2 proteins (3), which, containing a JmjC domain, are lysine trimethyl-specific histone demethylases capable of catalyzing the demethylation of trimethylated H3K9 (H3K9me3) and H3K36 (H3K36me3) (6–8). The gene discussed is KDM4A; the disease is cancer.