KDM4A and cancer: An early study described a variety of inhibitor scaffolds with the capacity to suppress 2-OG-dependent JMJD2 histone demethylases, which would facilitate the establishment of small-molecule probes for the identification of enzyme functions in epigenetic signaling.390 Known JMJD2 inhibitors can be classified as either 2-OG cofactor mimics, substrate-competitors, metal cofactor inhibitors, and peptide inhibitors.391 Cofactor mimics competitively binding to Fe(II) at the catalytic site of JMJD2 proteins and modifies the availability of the 2-OG cofactor required for cancer cell metabolism.