NLK and head and neck squamous cell carcinoma: Among these genes, the expression levels of 12 genes (ABCA1, ADRBK2, ANKRD52, DEPDC1B, FXR1, ITGA3, KLF12, NLK, PCDH17, PDE7A, PXN, and SLC24A2) were significantly upregulated in HNSCC tissues (n = 518) compared with normal tissues (n = 44) (Figure 2).