Elevated levels of serum metalloproteinase 9 in patients with esophageal squamous cell carcinoma

Introduction Matrix metalloproteinase 9 (MMP‑9) is a proteolytic enzyme which is associated with tumor progression including invasion, migration, angiogenesis, and metastasis due to its ability to degrade type IV collagen. Objectives The aim of the study was to assess clinical significance of MMP‑9 measurement in the diagnostic evaluation of patients with esophageal squamous cell carcinoma (ESCC). Patients and methods The study included 63 patients with ESCC and 30 healthy subjects. We assayed serum MMP‑9 levels and squamous cell carcinoma antigen (SCC‑Ag), a tumor marker. We defined diagnostic criteria for both markers. Results In ESCC patients serum levels of MMP‑9 and SCC‑Ag were found to be statistically higher compared with healthy subjects. Serum concentrations of MMP‑9 and SCC‑Ag tended to increase in patients with advanced cancer. The percentage of elevated MMP‑9 concentrations (75%) was higher than that of SCC‑Ag (68%) and increased for the combined use of both markers (97%). Conclusions The results suggest the potential usefulness of MMP‑9 in establishing the diagnosis of ESCC, especially when analyzed in combination with SCC‑Ag.