Background: JMJD2A is a member of the jumonji (jmj) domain containing gene family of histone demethylases that plays a role in chromatin regulation and influences transcriptional activation and suppression. Some recently characterized members of the jmj family include JARID1A/RBP2, JARID1C, JMJD1A, JMJD1B, JMJD1C, JMJD2A, JMJD2C and JMJD2D. JMJD2A is a trimethylation-specific demethylase and functions as a transcriptional repressor. JMJD2A interacts with pRb and class one histone deacetylases to mediate repression of E2F-regulated promoters.