Consistent with other bioinformatic analysis, a significant overexpression of DKK1 was revealed in head and neck squamous cell carcinoma (HNSC), pancreatic adenocarcinoma (PAAD), and lung squamous cell carcinoma (LUSC), with DKK1 overexpression being associated with shorter disease-free survival (DFS) (42). This evidence concerns the gene DKK1 and squamous cell lung carcinoma.