Osteosarcoma is the most frequent primary malignant bone tumour in children and adolescents with a high propensity for metastasis and therefore poor prognosis. Despite the significant clinical improvements made over the past decades through the combined chemotherapeutic and surgical treatment, patients with metastatic or recurrent disease continue to have a very poor prognosis, with a 5-year survival rate of 10-20%. Metastatic tumours are often refractory or only partially sensitive to current therapeutic strategies and are the primary cause of cancer-related mortality. It is clear that current treatment strategies including the combination of chemotherapy and surgery are unable to combat metastatic disease in patients with OS, and new avenues, e.g. prevention of metastasis, need to be explored to address this problem.
The molecular mechanisms which lead to metastasis are yet poorly understood. Understanding these mechanisms will allow to identify drug targets and to rationally design corresponding drugs. Therefore, identification of key regulatory molecules involved in OS metastasis is crucial, not only for a basic understanding of the molecular and cellular processes involved, but also to devise novel targeted and rational therapeutic strategies.