Considerable attention has converged on those JMJD proteins reported with histone lysine demethylase activity.23 Though some other JMJD family members are not catalytically active, such as JARID2, which contains amino acid mutations critical for cofactor binding, they are still essential for the multiple biological processes.24 In this review, we will focus on the role of JMJD family proteins in cancer and inflammation, including the intensively studied histone lysine demethylases and the understudied group of JMJD members. The gene discussed is JARID2; the disease is cancer.