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]. This evidence concerns the gene AK4 and osteosarcoma.