In addition, Ogata T. et al. showed that the low dose of photon irradiation increased the gene expression and the protein activity of MMP2 and MMP9, and they promoted the metastatic potential of human fibrosarcoma cell line HT1080 and mouse osteosarcoma cell line LM8 cells, while the biological equivalent dose of C-ion irradiation suppressed the metastasis25. This evidence concerns the gene MMP9 and osteosarcoma.