STAT3 and osteosarcoma: Several pathways, including mitogen-activated protein kinases (MAPKs), a family of serine/threonine kinases, including extracellular signal–regulated kinase (ERK) 1/2, c-Jun N-terminal kinase (JNK) 1/2 and p38, phosphoinositde 3-kinase (PI3K)/Akt, nuclear factor κB (NF-κB), and Janus kinase (JAK)/signal transducer and activator of transcription 3 (STAT3), are known to participate in various signaling cascades that are involved in the many cellular processes of motility, migration, invasion, and adhesion in osteosarcoma [13,14,15,16].