STAT3 and osteosarcoma: Moreover, in osteosarcoma cells, miR-199a-3p targeted mTOR, mesenchymal to epithelial transition factor(Met), signal transducer and activator of transcription 3(Stat3), adenylate kinase 4(AK4), and AXL receptor tyrosine kinase (AXL) respectively, blocking the proliferation, invasion, and metastasis of tumor cells through a complex signaling network pathway [54,55,56].