JAK2 and osteosarcoma: Human osteosarcoma samples with MSC-related features were shown to be genetically distinct from the remaining tumor cells, indicating that maintaining a unique niche may be essential for keeping osteosarcoma cells in an undifferentiated condition [71], which has also been demonstrated to encourage osteosarcoma growth and metastasis by activating STAT3 [72] and to induce doxorubicin resistance through JAK2/STAT3 signaling [73].