MMP9 and neoplasm: Via the process of hydrolysis, the activated MMP‐9 is able to degrade basement membrane (BM) type IV collagen, which is believed to affect the ability of BMs to impede tumour cell movement.13 As type IV collagens are the main components of the extracellular matrix and BMs, tumour‐derived MMP‐9 may destroy these tissue barriers and enhance the invasion and metastasis of tumour cells.