In addition, treatment with anti-tumour agents promoted up-regulation of EGR1. Although forced expression of EGR1 did not affect osteosarcoma growth, forced expression of EGR1 inhibited osteosarcoma cell invasion by down-regulation of urokinase plasminogen activator (uPA) and urokinase receptor (uPAR). This evidence concerns the gene PLAU and osteosarcoma.