Subgroup analysis based on age showed that higher MMP-7 protein expression was detected in lung cancer patients with TNM stage III-IV compared to TNM stage I-II in all patients under age 60 (OR = 2.43, 95% CI: 1.53 to 3.87, P <0.001), while there was no such statistically significant differences in patients over 60 years age (OR = 1.71, 95% CI = 0.92-3.16, P = 0.09). This evidence concerns the gene MMP7 and lung cancer.