A lower MMP-7 protein expression was detected by using SP in lung cancer patients with histologic grade 3 to 4 than that in patients with histologic grade 1 to 2 (OR = 2.02, 95% CI: 1.17 to 3.50, P = 0.011), while the difference of MMP-7 protein expression by using Non-SP between lung cancer patients with histologic grade 3 to 4 and patients with histologic grade 1 to 2 showed no statistical significance (P = 0.251) (as seen in Figure 3). This evidence concerns the gene MMP7 and lung cancer.