Correlation Between Serum Matrix Metalloproteinase-9 (MMP-9) and Tissue Inhibitor of Metalloproteinase -1 (TIMP-1) Levels and the Clinical Characteristics of Patients with Pleural Effusion

Abstract Background: Clinically, it can be difficult to distinguish between benign and malignant exudative pleural effusion (PE), and in certain cases. MMP-9 contributes to persistent inflammation and is linked to the aggressivity and metastatic potential of tumors. Objectives: The aim of the present study was to determine the correlation between matrix metalloproteinase-9 and tissue inhibitor of metalloproteinase-1 and to distinguish between benign and malignant exudative pleural effusions. Materials and Methods: This is a case-control study comprising 60 patients with malignant PEs and 60 patients with benign PEs who visited the medical city – Baghdad Hospital. All patients were examined and asked about their medical history, and they measured the levels of serum MMP-9 and TIMP-1 in the serum as markers for differentiation between benign and malignant exudative pleural effusion. It was determined by using the quantitative sandwich (ELISA) technique. Results: It was observed that there is a strong positive correlation between MMP-9 and TIMP-1 with P value = 0.007 in Benign PEs and ( P < 0.001) in Malignant PEs. It was found that patients with malignant pleural effusion have greater serum levels of MMP-9 and TIMP-1 than patients with benign pleural effusion with mean ± SD of MMP-9 ng/mL are 12.79 ± 5.15 in MPEs and 7.95 ± 2.82 in BPEs, whether mean ± SD of TIMP-1 pg/mL are 1150.56 ± 476.79 in MPEs and 665.51 ± 350.63 in BPEs. Conclusions: Our results showed that there is a strong positive correlation between MMP-9 and TIMP-1 indicating that as serum MMP-9 levels increase, serum TIMP-1 level also tends to increase significantly. Also, MMP-9 and TIMP-1 might be valuable markers in differentiating benign from malignant pleural effusions.