MMP9 and neoplasm: Tumour‐associated proteases are required for metastasis, invasion and migration.51 Metalloproteinases (MMPs) are believed to be essential for extracellular matrix degradation, a significant characteristic of OS invasion and metastasis.52 In the present study, Tan I suppressed the mRNA and protein expression of MMP‐2 and MMP‐9, possibly responsible for OS cell invasion and metastasis (Figure 5B,C).