KDM5A (JARID1A, RBP2) is a retinoblastoma RB-binding protein and mediates metastasis in estrogen receptor-negative breast cancers [15], while KDM5B (JARID1B or PLU-1) has roles in tumor maintenance [16], melanoma metastatic progression and resistance to cytotoxic agents and BRAF inhibitors [13]. The gene discussed is KDM5B; the disease is melanoma.