PLAUR and squamous cell carcinoma: Aguirre-Ghiso et al. reported that urokinase plasminogen activator receptor (uPAR) downregulation induces tumor dormancy in vivo through the inhibition of the physical interaction of uPA/uPAR complexes with the α5β1 integrin, resulting in lower adhesion of human squamous carcinoma cells to fibronectin and lower MAPK/ERK pathway activation (66).