MAPK3 and osteosarcoma: In the past 10 years, several cell signaling pathways, including phosphoinositide 3 kinase (PI3 K)/Akt, extracellular signal-regulated kinase (ERK)1/2, Notch, and Wnt-β-catenin, have been identified to be involved in osteosarcoma chemoresistance [24–26].