S100A9 and head and neck squamous cell carcinoma: Downregulation of S100A8 and S100A9 genes in HNSCC did not correlate with regional lymph node involvement (N stage) (Figure 2C) or distant metastases (M stage) (Figure 2C and 2D), suggesting that S100A8/A9 dysregulation contributes to initiation of malignancy.