Expression of Urokinase‐type Plasminogen Activator (uPA), uPA Receptor, and Plasminogen Activator Inhibitor‐1 in Oral Squamous Cell Carcinoma

Abstract We investigated whether the expression levels of urokinase‐type plasminogen activator (uPA), uPA receptor (uPAR), and plasminogen activator inhibitor‐1 (PAI‐1) correlate with clinicopathological features of oral squamous cell carcinoma (SCC). We immunohistochemically examined the expression levels of uPA, uPAR, and PAI‐1 in 160 biopsy specimens of oral SCC. Positive stainings for uPA, uPAR, and PAI‐1 were observed mainly in SCC cells, and their intensity and number of positive cells were related to lymph node involvement ( p < 0.001, p < 0.001, and p < 0.001, respectively). The expression levels of uPA and uPAR were also related to the pattern of invasion ( p < 0.05 and p < 0.001, respectively), while both were associated with tumor size ( p < 0.05). Moreover, a poor survival rate was related to the expression of uPAR ( p < 0.01) and PAI‐1 ( p < 0.05). These findings suggest that the uPA system may regulate the invasion and metastasis of oral SCC cells.