APP and head and neck squamous cell carcinoma: Consistent with the result of the risk score, the results of PLAU, APP and VEGFA also showed that the mRNA expression levels of IL-1α, IL-1β, IL-6 and IL-8 in HNSCC samples with high expression of PLAU, APP and VEGFA were significantly higher than those with low expression (all P < 0.05, Figure 9B–9D).