Introduction

More than 20% of patients with osteosarcoma die of the disease within 5 years due to tumour relapse and metastasis. Identifying new treatment that works singly or in combination with conventional therapies is urgently required. We previously found that the Ras/Raf/MAPK pathway was associated with lung metastasis in a 143B inoculated osteosarcoma orthotopic mouse model¹. Sorafenib, a multi-kinase inhibitor, has shown potent anticancer effect including in osteosarcoma² through the inhibition of Raf-1 and other targets³. The aims of this study were to investigate effect of sorafenib on osteosarcoma cell lines with or without activated Ras/Raf/MAPK signalling and to decide whether sorafenib could enhance irradiation on these cells.