MMP-7 protein expression in lung cancer with histologic grade 3 to 4 was remarkably higher than histologic grade 1 to 2, which was not influenced by age (Age <60: OR = 1.63, 95% CI = 1.08 to 2.47, P = 0.021; Age ≥ 60: OR = 1.56, 95% CI = 1.02-2.38, P = 0.041) (as shown in Figure 3). Here, MMP7 is linked to lung carcinoma.