2.10. In Vivo Tumor Xenograft Study

All mice were obtained from the Lasco (Taipei, Taiwan). Ethical approval was obtained for the use of the animals, and all experiments were performed in accordance with the Guidelines for Animal Care of the Institutional Animal Care and Use Committee of College of Medicine, National Taiwan University (Approval No: 20150357). All experiments were performed in National Taiwan University. Four-week-old male CB17/SCID mice were purchased from Lasco and maintained under pathogen-free conditions. Seven animals per group were used, and the experiment was repeated twice. For assessing lung metastasis in osteosarcoma cells in the in vivo xenograft model. Two times 1 × 10⁶ cells were resuspended in 0.1 mL of PBS and injected into the lateral tail vein. After 4 weeks, mice were sacrificed using CO₂. The lungs were removed and fixed in 10% formalin. The number of lung tumor nodules was counted using a dissecting microscope.