Circulating uPA as a potential prognostic biomarker for resectable esophageal squamous cell carcinoma

Previous research showed that the 4 genes of matrix metallopeptidase 9 (MMP9), cyto-keratin 20 (CK20), cyto-keratin 19 (CK19) and urokinase type plasminogen activator (uPA) are detectable in the peripheral blood. All the 4 genes are related to tumor invasion and metastasis. However, whether their expression is associated with clinicopathologic factors and the prognosis of patients with esophageal squamous cell carcinoma (ESCC) is still confused. Expression levels of MMP9, CK20, CK19, and uPA were evaluated by quantificational real-time polymerase chain reaction (qRT-PCR) in peripheral blood of 205 ESCC patients who received radical resection. The cut-off value was 1000 copy numbers. Their impacts on clinicopathologic factors and survival were investigated. The uPA expression positively correlated with gender (P = .046) and tumor size (P = .046). Meanwhile, CK19 expression positively correlated with tumor size (P = .029), vascular invasion (P = .024), and CK20 expression positively correlated with tumor size (P = .035) and degrees of differentiation (P = .032). Moreover, the overexpression of MMP9 has a correlation with postoperative radiotherapy (P = .041) and chemotherapy (P = .012). Among the 4 genes, only uPA is a prognostic indicator for disease-free survival and overall survival both in univariate analysis and multivariate analysis (P = .015). This study suggests that circulating uPA mRNA in peripheral blood can serve as a potential unfavorable prognosis biomarker in ESCC. Further perspective, multi-center and large-scale study is still needed.