RAB22A and osteosarcoma: Furthermore, using the orthotopic osteosarcoma metastasis model in vivo, the enhancement of lung metastases was abolished in both 143B-Luc and U2OS/MTX300-Luc cells treated with exosomes derived from ZOS-M cells stably knockdown RAB22A-NeoF1 compared to those derived from ZOS-M control cells (Fig. 2f–h and Supplementary Fig. 2i).