Association between cyclooxygenase-2 and matrix metalloproteinase-2 expression in non-small cell lung cancer

Background: Cyclooxygenase-2 (COX-2) contributes to invasiveness of cancer through activation of several matrix metalloproteinases (MMPs). Matrix metalloproteinase-2 (MMP-2) is a proteolytic enzyme that degrades the extracellular matrix, and has been linked to invasion and metastasis. This study aims to assess the correlation of the COX-2 expression and the MMP-2 expression in patients with non-small cell lung cancer (NSCLC). Methods: We analyzed the protein expressions of COX-2 and MMP-2 by immunohistochemical staining on the tissue array specimens from 204 patients with completely resected NSCLC. A < 10% immunostaining of the cancer cells was considered negative, while > 10% was considered positive. Results: The COX-2 expression was positive in 68.1% and that of the MMP-2 was positive in 45.6%. The positive expression rate of MMP-2 (52.5%) in the positive COX-2 group was higher than that in the negative COX-2 group (30.8%, P = 0.004). Furthermore, the MMP-2 expression was associated with lymph node involvement, the tumor stage and the histological type. The patients with a positive MMP-2 expression showed a reduced survival (P = 0.048). Conclusions: The COX-2 expression is associated with the MMP-2 expression in NSCLC patients: the latter may also be associated with tumor progression and reduced survival in NSCLC patients.