Interestingly, PAI-1 expression significantly increased (P < 0.05) in poorly differentiated HNSCC samples compared with well-differentiated HNSCCs (Grade III vs. Grade I; Grade IV vs. Grade I; Grade IV vs. Grad II, P<0.05 respectively, Fig. S2B). The gene discussed is SERPINE1; the disease is head and neck squamous cell carcinoma.