Consistent with this hypothesis, expression of PAI‐1 and MMP‐13 were very poor in miR‐143 higher expressing osteosarcoma primary lesion (Fig. 5), and PAI‐1 and MMP‐13 double‐positive clinical samples (group 4) showed a significantly higher chance of lung metastasis than any of the other groups as shown in Figure 6. This evidence concerns the gene SERPINE1 and osteosarcoma.