Accumulating evidence suggests that aberrant regulation of chromatin modification is important to tumorigenesis.Histone methylation is the posttranslational modification of histone amino acids by addition of methyl groups that regulates chromatin structure, transcription, and cellular epigenetic status. The jumonji (jmj) domain containing gene family of proteins has been discovered to play a role in chromatin regulation by influencing transcriptional activation, suppression, and demethylation. Some recently characterized members of the jmj family of histone demethylases include JARID1A/RBP2, JARID1C, JMJD1A, JMJD1B, JMJD1C, JMJD2A, JMJD2C and JMJD2D. Two members of this protein family, JARID1A/RBP2 and JMJD2A, have been found to bind the tumor suppressor protein pRb further strengthening the role of these proteins in transcriptional regulation. Additionally, JMJD2C, a lso known as GASC1 (gene amplified in squamous cell carcinoma), has been found to be amplified in several espophageal squaumous carcinomas and inhibition of JMJD2C/GASC1 expression results in decreased cellular proliferation. Therefore, histone demethylases can be viewed as an up and coming target of research for anti-cancer therapies.