DUSP1 and osteosarcoma: Another explored pathway suggests that triptolide reduces osteosarcoma cell viability by decreasing the expression of mitogen-activated protein kinase phosphatase 1 (MKP–1), a repressor of MAPK signalling pathway, and that of heat shock protein 70 (Hsp70), a chaperone whose increased levels are speculated to contribute in chemoresistance [105].