We observed the percentage of KDM5A-positive (KDM5A+) (Fig. 2B), Ki67-positive (Ki67+) (Fig. 2C), and KDM5A+/Ki67+ double-positive (Fig. 2D) cells in the malignant osteosarcoma group was significantly higher than in the normal group, which was correlated with Enneking stages. The gene discussed is MKI67; the disease is osteosarcoma.