MMP9 and lung cancer: Overexpression of MMPs, in particular gelatinase A (MMP-2), gelatinase B (MMP-9) and stromelysin-3 (MMP-11), is related to tumour progression and metastasis in solid tumours including gastric (Schwartz, 1996), colon (Karakiulakis et al, 1997) and lung cancer (Cox et al, 2000b).