RPN2 and osteosarcoma: Doxorubicin and methotrexate are standard drugs for treatment of osteosarcoma, the former being especially effective.24 Since osteosarcoma patients who show a poor response to these drugs have a poor prognosis,10,18 silencing of RPN2 in osteosarcoma tissue would improve prognosis by sensitizing the cancer cells to these drugs.