The level of expression of Mmp-2 and Mmp-3 was comparable in normal lung and tumor tissue (median 2-ddCT = 0.24 vs. 0.47; p = 0.03 and 0.16 vs. 0.29; p = 0.28, respectively) whereas the relative expression of Mmp-9 was significantly lower in cancerous tissue as compared to normal lung (median 2-ddCT = 0.23 vs. 0.60; p = 0.008). This evidence concerns the gene MMP3 and neoplasm.