Expression and Clinical Significance of MMP-1 and MMP-7 in Pneumonia, Pulmonary Fibrosis, and Lung Cancer

This study aimed to investigate the expression levels and clinical significance of matrix metalloproteinase-1 (MMP-1) and matrix metalloproteinase-7 (MMP-7) in patients with pneumonia, pulmonary fibrosis (PF), and lung cancer (LC). A total of 136 pneumonia cases, 15 PF cases, 64 LC cases, and 47 healthy controls were retrospectively included from Shaanxi Provincial Nuclear Industry 215 Hospital between October 2023 and April 2024. Serum concentrations of MMP-1 and MMP-7 were quantified using chemiluminescence immunoassay. Positivity rates were compared across groups, and Spearman's correlation was used to examine the association between age and MMP expression. Receiver operating characteristic (ROC) analysis was performed to determine optimal cut-off values and assess diagnostic performance. Median serum MMP-1 levels were higher in the LC group (22.9 ng/mL; IQR: 11.65-30.0) and PF group (26.5 ng/mL; IQR: 14.4-30.0) compared with the pneumonia group (15.4 ng/mL; IQR: 9.34-28.75) (p < 0.05). Similarly, MMP-7 levels were elevated in the LC (4.52 ng/mL; IQR: 3.55-6.20) and PF (5.05 ng/mL; IQR: 4.00-7.44) groups compared with the pneumonia (2.35 ng/mL; IQR: 1.87-3.36) and healthy control (2.27 ng/mL; IQR: 1.88-2.81) groups (p < 0.05). Significant intergroup differences in positivity rates were observed (p < 0.05). Age was positively correlated with both MMP-1 (rs = 0.215, p < 0.001) and MMP-7 (rs = 0.531, p < 0.001), with the correlation stronger for MMP-7. No statistically significant differences were found between sexes for MMP-1 (z = -1.033, p = 0.301) or MMP-7 (z = -1.326, p = 0.185). MMP-7 demonstrated high diagnostic accuracy for LC (cutoff = 3.325 ng/mL; sensitivity = 84.4%; specificity = 97.9%) and PF (cutoff = 3.66 ng/mL; sensitivity = 80.0%; specificity = 97.9%). In contrast, the diagnostic performance of MMP-1 and MMP-7 for pneumonia was relatively limited. These findings suggest that MMP-7 may serve as a useful non-invasive biomarker for differentiating between PF and LC, while the clinical utility of MMP-1 remains limited due to low specificity.