Prognostic significance of matrix metalloproteinase-1 levels in peripheral plasma and tumour tissues of lung cancer patients.

Matrix metalloproteinase-1 (MMP-1) participates in a variety of physiological and pathological processes. We previously found that MMP-1 was one of the lung cancer-related proteins detectable in peripheral blood. To validate our preliminary observations and explore the clinical significance of MMP-1 for lung cancer further, we carried out the present study. The concentrations of MMP-1 in circulating plasma specimens of 170 lung cancer patients and 70 healthy individuals were measured by an enzyme-linked immunosorbance assay. The expression status of the MMP-1 in archival tissue samples from 122 lung cancer patients was examined by immunohistochemical analysis. The correlation between the MMP-1 levels and prognosis of the lung cancer patients was then assessed statistically. Protein levels of MMP-1 were considerably raised in the plasma from lung cancer patients relative to those in healthy controls. The high plasma MMP-1 levels were associated with advanced-stage of the disease and significantly lower overall survival rate of the patients. Coincidently, MMP-1 protein extraordinarily overexpressed in the tumour tissues of lung cancer; and the up-regulated MMP-1 was associated with the progression (including tumour size, staging and lymphatic invasion), especially with decreased survival rate of the patients. Statistic analysis revealed that MMP-1 protein levels had an independent influence on survival. MMP-1 levels were elevated in both tumour tissue and blood; the latter may serve as an independent predictor for survival of lung cancer patients. MMP-1 protein levels in plasma/serum thus represent a potential and clinically relevant biomarker for the prognosis of patients with lung cancers.